deepen

deepen — verb

1. to dig or cut a hollow space such as a hole, well, or channel so that it reaches

1.verbtransitive / intransitiveB1
Definition

to dig or cut a hollow space such as a hole, well, or channel so that it reaches further down, or for such a space to grow deeper on its own

Example

The workers deepened the well so the village would have more water.

transitive: deepen + physical object (well, hole, channel)

As Lakan dug, the hole deepened quickly in the soft soil.

intransitive: hole / river deepens

Common collocations
  • deepen a well
  • deepen a channel
  • deepen a hole
  • deepen a river
  • deepen a harbor
  • deepen a trench
Synonyms
  • dig out

    less formal, refers to the action of removing material rather than the result

  • scoop out

    implies using a scooping tool; more specific to small-scale actions

Antonyms
  • fill in

    opposite action — adding material to reduce depth

  • shallow

    rarely used as a verb; 'become shallower' is the common expression

Grammar Patterns

deepen + object (hole, well, river, channel)

something deepens (the hole, river, channel deepens)

Usage Note

Common with physical objects such as wells, holes, channels, rivers, and containers. The intransitive use often describes natural processes like erosion or excavation.

Common Mistakes

They deepened the hole more deeper.
They deepened the hole further.
'deepen' already includes the idea of becoming deeper; 'more deeper' is a double comparative.

2. when an emotion such as love, trust, or concern grows stronger over time, or whe

2.verbtransitive / intransitiveB1
Definition

when an emotion such as love, trust, or concern grows stronger over time, or when a person or experience makes that feeling more powerful

Example

Ife's love for her community deepened over the years she volunteered there.

intransitive: feeling deepens over time

Nikhil's frustration deepened when he could not fix the broken pipe himself.

Common collocations
  • deepen love
  • deepen trust
  • deepen respect
  • deepen concern
  • deepen a bond
  • deepen a relationship
  • deepen over time
  • deepen with age
Synonyms
  • intensify

    more forceful; often used for negative emotions (anger, fear)

  • heighten

    suggests an increase in awareness or sensitivity rather than emotional power

  • strengthen

    broader; can apply to relationships, bonds, or resolve

Antonyms
  • weaken

    the most direct opposite for feelings and emotions

  • fade

    suggests gradual loss of emotional strength over time

Grammar Patterns

deepen + object (love, trust, respect, concern)

something deepens (a feeling, emotion, bond deepens)

deepen + over time

Usage Note

Often used with emotion nouns: love, trust, respect, sadness, worry, fear, frustration. The intransitive form commonly pairs with 'over time' or 'as' to show gradual change.

Common Mistakes

Her love deepened for him.' (sounds awkward in English)
Her love for him deepened.
place 'for [person]' before the verb in the intransitive pattern.

3. to become more serious or extreme, or to make a problem, disagreement, or unders

3.verbtransitive / intransitiveB2
Definition

to become more serious or extreme, or to make a problem, disagreement, or understanding greater in degree

Example

The economic crisis deepened as more factories closed across the region.

intransitive: crisis / problem deepens

Asher's year abroad deepened his understanding of Japanese culture.

transitive: deepen understanding / knowledge of something

Common collocations
  • deepen a crisis
  • deepen a conflict
  • deepen a recession
  • deepen understanding
  • deepen knowledge
  • deepen awareness
  • deepen a division
Synonyms
  • intensify

    more common for negative situations (conflict, crisis); slightly stronger in tone

  • worsen

    exclusively negative; cannot be used for knowledge or understanding

  • escalate

    implies a step-by-step increase; often used for conflict or tension

Antonyms
  • ease

    suggests a reduction in seriousness or intensity

  • resolve

    specifically for problems or disagreements being settled

  • lessen

    general opposite for degree or intensity

Grammar Patterns

deepen + object (crisis, conflict, understanding, knowledge)

something deepens (a problem, crisis, recession deepens)

deepen + understanding / knowledge + of

Usage Note

Can apply to negative situations (crisis, conflict, recession) or positive intellectual growth (knowledge, understanding). The positive use with 'understanding' or 'knowledge' is common in educational and professional contexts.

Common Mistakes

I want to deepen my knowledge about history.
I want to deepen my knowledge of history.
'deepen knowledge' takes 'of', not 'about'.

4. if a voice or sound deepens, it becomes lower in tone or pitch

4.verbtransitive / intransitiveB2
Definition

if a voice or sound deepens, it becomes lower in tone or pitch

Example

Haruto's voice deepened when he turned fourteen years old.

intransitive: voice deepens with age

Eric deepened his voice to sound more serious during the presentation.

transitive: deepen + voice deliberately

Common collocations
  • voice deepens
  • deepen the voice
  • deepen a tone
  • deepen a sound
Synonyms
  • lower

    more general; 'lower your voice' often means speak more quietly, not at a lower pitch

Antonyms
  • rise

    opposite direction in pitch; 'his voice rose in excitement'

  • raise

    transitive opposite — 'raise your voice' means speak louder or at a higher pitch

Grammar Patterns

deepen + object (voice, sound)

something deepens (voice, sound, tone deepens)

Usage Note

Typically describes natural voice change during adolescence or deliberate vocal control for dramatic effect. Less common with non-human sounds, though possible (e.g., 'the engine's roar deepened').

5. to become darker and richer in colour or shade, or to make something this way

5.verbtransitive / intransitiveB2
Definition

to become darker and richer in colour or shade, or to make something this way

Example

The evening sky deepened to a rich shade of purple as the sun set.

intransitive: sky / colour deepens

João deepened the blue in his painting by adding a second layer of paint.

transitive: deepen + colour in art

Common collocations
  • sky deepens
  • colour deepens
  • shadows deepen
  • deepen a colour
  • deepen a shade
  • deepen the blue / red / green
Synonyms
  • darken

    more direct and common; 'deepen' adds a sense of richness and saturation

  • intensify

    broader; can apply to any colour attribute, not just darkness

Antonyms
  • lighten

    the most direct opposite — make paler or brighter

  • fade

    suggests loss of colour intensity, not just brightness

Grammar Patterns

deepen + object (colour, shadow)

something deepens (sky, colour, shadow deepens)

Usage Note

Frequently used with natural light changes (sky, shadows, twilight) and in artistic contexts (paint, dye, photography). Often implies a richer, more saturated darkness rather than simply 'darker'.

Word family

Synonym discussion

Sense: verb/2

Deepen, intensify, heighten, amplify, and strengthen all describe an increase in degree, but they differ in scope and connotation. Deepen suggests a gradual, inward change that adds richness or seriousness — emotions, relationships, and understanding 'deepen' over time. Intensify is more forceful and often carries a sharper edge; crises and conflicts intensify, and it can sound more dramatic than deepen. Heighten focuses on raising awareness or sensitivity rather than emotional power — you heighten alertness or tension. Amplify literally means 'make larger' and is often used for sound or signals, but metaphorically it means to exaggerate or magnify (e.g., 'the media amplified the scandal'). Strengthen is the broadest term and applies to anything made physically or metaphorically stronger — muscles, arguments, relationships, or resolve. For a feeling growing richer and more powerful, deepen is the most natural choice: 'Their friendship deepened over years of shared experience' sounds more natural than 'Their friendship intensified.'

intensify ↗heighten ↗amplifystrengthen ↗

Common collocations

Nouns

Adverbs

Phrases

  • over time
  • with age
  • in tone
  • in colour
  • in depth
  • over the years

Prepositions

Etymology

Old EnglishMiddle EnglishEnglish

Deepen comes from the adjective 'deep' (Old English 'deop', meaning 'having great depth') plus the suffix '-en', which turns adjectives into verbs meaning 'to make or become'. This '-en' suffix is the same one found in 'widen', 'broaden', 'strengthen', and 'darken'. The word has been in English since the 14th century, originally used for physical depth and later extended to emotions, sounds, and colours.