deep
deep — noun
1. a word used in poetry and literature to refer to the sea, often suggesting its m
a word used in poetry and literature to refer to the sea, often suggesting its mystery, power, or vast size.
The old fisherman set sail across the deep, searching for a good catch.
literary use: 'the deep' for the sea
Legends say that strange creatures live in the deep.
in the deep
Yumi stood on the cliff, watching the deep stretch endlessly toward the horizon.
For generations, sailors have told frightening stories about the deep.
Sari watched the waves of the deep crash against the rocks far below the lighthouse.
narrative literary context: 'the deep' = the sea, with waves/rocks/lighthouse as clues
- the deep
- across the deep
- in the deep
- into the deep
- over the deep
- from the deep
Grammar Patterns
the deep
Usage Note
Always used with the definite article 'the'. This sense is primarily found in literary, poetic, or religious texts rather than everyday conversation.
Common Mistakes
2. the part of something that is farthest from its surface or outer edges; also use
the part of something that is farthest from its surface or outer edges; also used to describe the time when a feeling, season, or condition is at its most intense.
The treasure lay hidden in the deep of the forest.
in the deep of + place
Eitan could feel the cold in the deep of his bones.
In the deep of winter, the village is often cut off by snow.
in the deep of winter
Isabela found courage in the deep of her heart when she needed it most.
The story touched the deep of my emotions in a surprising way.
- the deep of winter
- the deep of night
- the deep of the forest
- the deep of one's heart
- in the deep of
- into the deep of
Grammar Patterns
the deep of [something]
Usage Note
Typically follows the pattern 'the deep of + noun phrase'. Common collocates include 'winter', 'night', 'heart', 'forest', and 'soul'. This sense is less common in modern spoken English than the related adjective and adverb forms.
Common Mistakes
the deep
idioma poetic or literary term for the sea or ocean, often evoking mystery, danger, or grandeur.
The ancient poem speaks of monsters rising from the deep.
Sailors once believed that the deep was home to powerful sea gods.
deep — adjective
1. if something is deep, its bottom is far below its top or surface — used for hole
if something is deep, its bottom is far below its top or surface — used for holes, bodies of water, valleys, and similar features that reach far beneath their opening
The lake near Jisoo's village is too deep for swimming in summer.
deep + body of water (lake, river, sea)
Hugo fell into a deep hole and had to wait for help to arrive.
deep + hole / pit / well
This old well is over ten metres deep, so be careful near the edge.
number + metres / feet + deep (measurement)
Children should not swim in the deep end of the pool without an adult.
- deep hole
- deep water
- deep well
- deep end
- deep sea
- bottomless
suggests no visible bottom, often used poetically or for exaggeration
- yawning
formal or literary, describes a wide, deep opening like a crack or chasm
- shallow
having only a small distance from top to bottom
Usage Note
Commonly used with a number to state exact depth: 'two metres deep', 'six feet deep'. The opposite is shallow.
Common Mistakes
2. measuring a significant amount between its front side and its back side — used f
measuring a significant amount between its front side and its back side — used for shelves, cupboards, rooms, stages, and cuts that go well under the skin
Arjun's bookshelf is sixty centimetres deep and holds two rows of books.
number + unit + deep (horizontal measurement)
The cupboard is very deep, so we can store large pots and pans inside.
The stage was not deep enough for the whole dance group to perform.
deep enough (sufficiency pattern)
Nellie's wound was surprisingly deep and needed several stitches at the clinic.
- deep shelf
- deep cupboard
- deep stage
- deep wound
- deep cut
- wide
focuses on horizontal distance but does not specify front-to-back direction
- shallow
having little distance from front to back; also used for wounds
Usage Note
Often used with measurements: 'the shelf is 40 cm deep'. For wounds, deep refers to how far the cut goes below the skin surface.
3. located a long way from the outer edge or boundary of an area, or situated near
located a long way from the outer edge or boundary of an area, or situated near the centre of a space
Zuri got lost deep in the forest and found her way back using her phone.
deep + in + location (forest, jungle, cave)
The abandoned mine is deep inside the mountain and very hard to reach.
Deep space missions take years to reach planets beyond our solar system.
deep + space / territory / water (large-area contexts)
Kasia stood deep in the crowd and could not see the stage at all.
- deep in the forest
- deep inside the cave
- deep space
- deep in the crowd
- deep in enemy territory
Usage Note
Frequently followed by 'in' or 'inside' to specify the area: 'deep in the jungle', 'deep inside the cave'. Not used for sports-field positions — that sense is covered separately.
4. felt or experienced with great intensity, strength, or seriousness — used for em
felt or experienced with great intensity, strength, or seriousness — used for emotions, beliefs, states like sleep, or personal connections
Harper felt deep sadness after her grandmother passed away last winter.
deep + emotion (sadness, love, concern, fear)
The family has a deep respect for the traditions of their ancestors.
Tariq was in a deep sleep and did not hear his alarm clock ring.
deep sleep (fixed collocation)
Ife expressed deep concern about the rising cost of living in the city.
- deep love
- deep sadness
- deep concern
- deep respect
- deep sleep
- deep sense of
- shallow
lacking depth of feeling or seriousness
- superficial
not thorough or sincere
Usage Note
Commonly modifies abstract nouns for emotions (love, sadness, respect, concern) and states (sleep, trouble). Frequently used in formal or serious contexts. Distinguish from the 'fully involved' sense (sense 9) which describes active participation in an activity rather than the intensity of a feeling.
Common Mistakes
5. used for describing a sound or voice that is low in pitch, such as a man's deep
used for describing a sound or voice that is low in pitch, such as a man's deep voice or the bass notes of a cello — opposite of high-pitched
Cyrus has a deep voice that sounds great when he sings in the choir.
deep voice (common collocation for pitch)
The deep notes of the cello filled the concert hall with a warm sound.
Ignacio heard a deep rumble coming from inside the old factory walls.
deep + rumble / thunder / roar (low non-musical sounds)
The speaker produced a surprisingly deep bass tone for such a small box.
- deep voice
- deep sound
- deep note
- deep tone
- deep rumble
- high
having a high pitch
- high-pitched
having a high, thin sound
Usage Note
The opposite is high or high-pitched. Deep describes both musical notes (bass instruments) and non-musical sounds (thunder, engine noise).
6. showing serious thought, requiring careful study, or dealing with important, com
showing serious thought, requiring careful study, or dealing with important, complicated ideas — used for conversations, books, questions, and people who think thoroughly
Jisoo and Ayana had a deep conversation about the meaning of happiness.
deep + conversation / discussion / talk
The professor asked a deep question that made the whole class stop and think.
This novel is quite deep for a beginner reader because it explores difficult themes.
deep = difficult to understand (of text/film)
Indra is known as a deep thinker who always looks beyond the surface of things.
- deep conversation
- deep question
- deep thought
- deep thinker
- deep meaning
- profound
more formal, suggests great intellectual or spiritual importance
- thoughtful
focuses on the careful thinking involved, not necessarily on complexity
- complex
emphasises many parts or layers; does not necessarily imply importance
- shallow
not serious or thoughtful
- superficial
only dealing with obvious aspects
- simple
easy to understand
Usage Note
Can describe both the content itself ('a deep book') and a person's intellectual style ('a deep thinker'). Not usually used for academic subjects themselves — say 'advanced physics' rather than 'deep physics'.
Common Mistakes
7. describes a fielding position in baseball or cricket that is far from the batter
describes a fielding position in baseball or cricket that is far from the batter and close to the edge of the field
Jabari moved to a deep position near the boundary before the bowler began his run.
deep + noun for fielding position
The batter hit the ball deep into the outfield, and the runners advanced quickly.
Lakan was fielding at deep mid-wicket when the catch came his way.
deep mid-wicket as position name
Sivan chased the ball across deep centre field and threw it back to the infield.
- deep position
- deep field
- deep outfield
- deep mid-wicket
- deep centre field
- shallow
used in cricket and baseball for positions close to the batter
Grammar Patterns
deep + noun (fielding position)
Usage Note
Typically used before nouns that name specific fielding positions in baseball, cricket, and similar sports.
Common Mistakes
8. describes a colour that is dark and rich, not light or pale
describes a colour that is dark and rich, not light or pale
Lakshmi painted her bedroom walls a deep blue that reminded her of the ocean.
deep + colour as adjective before noun
Nora chose a deep green scarf to match her winter coat.
The leaves on the maple tree turned a deep red in late October.
turned + deep + colour
Lara wore a deep purple dress to the wedding reception.
- deep blue
- deep red
- deep green
- deep purple
- deep orange
Grammar Patterns
deep + colour
Usage Note
Commonly pairs with colour names such as blue, red, green, purple, and orange. Cannot be used with inherently light colours like 'white' or 'yellow' without sounding unnatural.
Common Mistakes
9. giving all your attention to an activity or mental state, so that you do not not
giving all your attention to an activity or mental state, so that you do not notice what is happening around you
Christopher was deep in thought and did not hear the phone ringing beside him.
deep in thought (common fixed phrase)
Tariq and Faisal were deep in conversation about the upcoming elections.
deep in conversation
The baby fell into a deep sleep after the long car ride home.
deep sleep (collocation for full unconsciousness)
Erik was deep in his book and did not notice the rain starting outside.
Antonia found herself deep in a difficult discussion about the company's future.
- deep in thought
- deep in conversation
- deep in a book
- deep sleep
- deep in discussion
- distracted
describes a lack of focus or attention
- unaware
being in a state of not noticing — opposite in result but different in structure
Grammar Patterns
deep in + noun/noun phrase
Usage Note
Distinguish from the emotion sense (adj/4): this sense describes the person's state of attention, not the intensity of a feeling. 'Deep in thought' means absorbed in thinking; 'deep love' means strongly felt emotion.
Common Mistakes
deep down
idiomused to describe what someone truly feels or believes, even if they do not show it openly
Deep down, Diya knew that moving abroad was the right choice for her career.
He looks confident on stage, but deep down he is very nervous before every show.
in deep water
idiomin a difficult or dangerous situation that is hard to escape from
The company is in deep water after losing its biggest customer last quarter.
Eric found himself in deep water when he agreed to manage three projects at once.
go deep (into)
idiomto examine or discuss something in great detail, going beyond the surface level
The reporter decided to go deep into the story about corruption in local government.
Their conversation went deep into the history of the conflict between the two nations.
to make someone start doing something new and difficult without giving them any help or preparation
The new teacher was thrown in at the deep end and had to manage a class of forty students on her first day.
Instead of training us first, the manager threw us in at the deep end with the biggest client account.
deep pockets
idioma large amount of money or financial resources available to a person or organisation
The tech startup has deep pockets and can afford to hire the best engineers in the world.
Smaller shops cannot compete with supermarkets that have deep pockets and lower prices.
Having to choose between two bad options, both of which are equally unpleasant.
Maya was between the devil and the deep blue sea when both job offers had low pay.
If you stay, you suffer; if you leave, you lose everything. You're between the devil and the deep blue sea.
in deep water(s)
idiomExperiencing serious trouble or difficulty.
After missing the deadline, Brian found himself in deep water with his boss.
Sara knew she was in deep water when she couldn't answer the judge's questions.
In a very bad or difficult situation, often due to a mistake.
If Dad finds out I broke his vase, I'll be in deep shit.
The company is in the shit after losing its biggest client.
deep — adverb
1. at a great distance beneath the surface or inside an object, such as the ground,
at a great distance beneath the surface or inside an object, such as the ground, water, or another material; far below or far inside a physical space.
The rescue team found the divers deep under the water near the shipwreck.
collocation: deep under [surface]
Mathieu dug deep into the earth to plant a new tree in his garden.
collocation: dig deep into
The roots of the old oak tree grew deep beneath the soil.
Aylin cut deep into the clay while shaping a bowl on her pottery wheel.
collocation: cut deep into
The submarine can travel deep below the ocean surface for months at a time.
collocation: deep below [body of water]
- dig deep
- cut deep
- sink deep
- swim deep
- go deep
- deep under
- deep below
- deep beneath
- deep into
- far down
more literal and explicit; used in instructional or technical contexts
- shallow
rare as an adverb; usually appears in phrase 'too shallow' or 'near the surface'
Grammar Patterns
deep + preposition (under/below/beneath/into)
verb + deep + prepositional phrase
Usage Note
Do not confuse with 'deeply', which is used before adjectives and past participles (e.g., 'deeply worried', 'deeply moved'). 'Deep' as an adverb comes after the verb and before a prepositional phrase of location.
Common Mistakes
2. in team ball sports, positioned in the defensive half of the field near the area
in team ball sports, positioned in the defensive half of the field near the area you are protecting, rather than in the middle of the pitch.
The coach told the defender to play deep and protect the goal.
collocation: play deep (defensive position)
Ramón stayed deep in his own half during the entire second half.
In rugby, the full-back usually stays deep to catch any long kicks from the other team.
pattern: stay deep + infinitive of purpose
The team's strategy was to keep three players deep near their own goal.
Pedro dropped deep into midfield to receive the ball from his goalkeeper.
collocation: drop deep into [area]
- play deep
- stay deep
- drop deep
- keep deep
- deep in one's own half
- far back
less technical; used in casual sports discussion
Grammar Patterns
play/stay/drop + deep
keep + [player] + deep
Usage Note
The opposite in sports is 'high' or 'forward', which means positioned closer to the opponent's goal. This sense is most common in British football commentary.
3. far into a period of time; continuing until an advanced or late stage of an even
far into a period of time; continuing until an advanced or late stage of an event, night, season, or other time frame.
The town council meeting ran deep into the night, ending just before midnight.
collocation: run deep into the night
Shanti continued studying deep into the evening before her final chemistry exam.
pattern: continue [verb]ing deep into [time period]
The wedding guests danced and sang deep into the early morning hours at the hotel.
Kasia worked deep into the winter nights on her PhD research paper.
The music festival in the park lasted deep into the following week.
collocation: last deep into [time period]
- deep into the night
- deep into the evening
- deep into winter
- deep into the season
- deep into the morning
- run deep into
- last deep into
- continue deep into
- work deep into
- early
at the beginning of a time period rather than deep within it
Grammar Patterns
deep into + [time period]
[verb] + deep into + [time period]
Usage Note
Almost always followed by 'into' and a noun phrase naming a time period. 'Deep' cannot be used alone to mean 'late' — you must specify what the late stage is (e.g., 'deep into the night', NOT 'deep at night').
Common Mistakes
deep down
idiomin a person's true feelings or character, especially when those feelings are different from how they appear on the surface.
Deep down, Sirin knew that her childhood friend was telling the truth about the accident.
Although Aoi seems very confident, deep down she worries about what others think of her.
Word family
Synonym discussion
Sense: adjective/1
Deep is the most general and frequently used word for describing physical downward distance (a deep hole), strong emotions (deep sadness), low pitch (a deep voice), and dark colours (deep purple). Profound is more formal than deep and is almost never used for physical depth or colours — it describes intellectual or spiritual significance (a profound insight, profound respect). Low overlaps with deep only for sound pitch: a low voice and a deep voice both mean a voice with a low register, but low is broader and can also describe volume (low whisper). Dark and rich overlap with deep for colours: deep blue emphasises saturation and intensity, while dark blue focuses on the absence of lightness; rich blue adds the idea of luxuriousness or vibrancy. Intense overlaps with deep for emotions and effort (intense sadness, intense focus) but cannot replace deep for physical measurements ('a deep hole' not 'an intense hole') or for colours in the same way. In daily use, choose deep for straightforward physical or emotional depth; use profound for serious, formal contexts; and pick dark/rich for colour descriptions depending on whether you want to emphasise shade or saturation.
Common collocations
Nouns
- deep breath
- deep sleep
- deep thought
- deep voice
- deep snow
- deep water
- deep trouble
- deep cut
- deep love
- deep concern
- deep end
Adverbs
- very deep
- quite deep
- surprisingly deep
- extremely deep
- fairly deep
Phrases
- deep down
- in deep water
- go deep into
- throw someone in at the deep end
- deep pockets
- still waters run deep
Prepositions
- deep in
- deep into
- deep under
- deep below
- deep beneath
- deep within
Etymology
Deep comes from Old English dēop, which traces back to Proto-Germanic *deupaz and further to the Indo-European root *dʰeup-, meaning 'deep, hollow'. This ancient root also gave rise to words like 'dive', 'dip', and 'depth' across Germanic languages.