keen

keen — adjective

1. feeling or showing a strong desire to take part in an activity or to see somethi

1.adjectiveB1
Definition

feeling or showing a strong desire to take part in an activity or to see something happen, often accompanied by active interest and effort.

Example

Layla is keen to join the school debate team next term.

keen + to + infinitive for personal desire

Stefan has always been keen on cycling and rides every weekend.

keen + on + gerund for enjoying an activity

Common collocations
  • keen interest
  • keen supporter
  • keen to learn
  • keen on football
Synonyms
  • eager

    more about impatience or excitement for a future event than ongoing interest

  • enthusiastic

    suggests livelier, more energetic interest than keen

  • avid

    stronger and more consuming interest, often in a hobby

  • zealous

    implies intense, sometimes extreme commitment

Antonyms

Grammar Patterns

keen + to + infinitive

keen + on + gerund/noun

Usage Note

In British English, 'keen on doing something' is a common everyday pattern. In American English, 'eager to' or 'enthusiastic about' are more typical for this sense.

Common Mistakes

I am keen on go to the cinema.
I am keen on going to the cinema.' or 'I am keen to go to the cinema.
After 'keen on,' use a gerund (-ing form), not the base verb.

2. having a very strong or powerful effect, such as a feeling (disappointment, desi

2.adjectiveB2
Definition

having a very strong or powerful effect, such as a feeling (disappointment, desire) or a situation (competition, rivalry) that involves deep intensity.

Example

The two runners share a keen rivalry that makes every race exciting.

keen + rivalry for intense competition

Padma felt a keen sense of disappointment when her visa application was denied.

keen + sense of + emotion noun

Common collocations
  • keen sense of disappointment
  • keen rivalry
  • keen desire
  • keen interest
Synonyms
  • intense

    more general; keen adds a sharper, more personal quality

  • acute

    slightly more formal and suggests a finely penetrating quality

  • fierce

    stronger and more aggressive, especially for competition

Antonyms

Grammar Patterns

keen + noun

Usage Note

This sense often pairs with abstract nouns describing feelings (disappointment, regret, desire) or competition (rivalry, contest, competition). It cannot describe physical sensations like pain.

Common Mistakes

I have a keen headache.
I have a bad headache.
Keen does not describe physical pain; use 'sharp' or 'intense' for pain instead.

3. able to think quickly, notice small differences, or perceive things with great a

3.adjectiveB2
Definition

able to think quickly, notice small differences, or perceive things with great accuracy — for example, a person with a keen mind solves problems fast, and a keen eye spots tiny details that others miss.

Example

Mira has a keen eye for colour and always picks the perfect paint shade.

keen + eye for perception of detail

A keen sense of smell helps the dog find food buried beneath the snow.

Common collocations
  • keen mind
  • keen eye
  • keen sense of smell/hearing/sight
  • keen judgement
Synonyms
  • sharp

    more informal and common in everyday speech

  • acute

    more formal; often used for senses like hearing or sight

  • perceptive

    focuses on understanding people and situations well

Antonyms

Grammar Patterns

keen + noun (mind / eye / sense)

Usage Note

Keen here describes the quality of a mental ability or physical sense — you have a 'keen mind' or 'keen eyesight,' not 'a keen person' (which would mean enthusiastic).

Common Mistakes

She is a keen student' (ambiguous — could mean enthusiastic or sharp-minded).
She has a keen mind for mathematics.
Use 'keen + ability noun' to clearly mean sharp-minded.

4. (of wind or cold air) blowing with sharp force and a very low temperature, often

4.adjectiveC1
Definition

(of wind or cold air) blowing with sharp force and a very low temperature, often cutting through clothing and making the skin feel as if it is being cut.

Example

A keen wind blew across the beach, forcing everyone to put on their jackets.

keen + wind for strong, cold air

The keen cold of the mountain air made Amani's fingers go numb within minutes.

Common collocations
  • keen wind
  • keen cold
  • keen air
  • keen frost
Synonyms
  • biting

    more common in everyday use; suggests a sharp, stinging quality

  • piercing

    emphasises the wind's ability to cut through clothing

  • icy

    focuses on low temperature rather than force

Antonyms

Grammar Patterns

keen + wind / cold / air

Usage Note

Only used for wind, cold, or frosty air. Not used for rain, snow, or other weather conditions. 'Biting' or 'piercing' are more common alternatives.

Common Mistakes

The rain was keen this morning.
The wind was keen this morning.
Keen describes wind or cold, not rain.

5. of a cutting tool or blade — made with a thin, sharp edge that can slice through

5.adjectiveB2
Definition

of a cutting tool or blade — made with a thin, sharp edge that can slice through materials such as food, wood, or fabric without requiring much force, found mainly in formal or descriptive writing about knives and tools.

Example

The old knife still has a keen blade that slices through tomatoes with ease.

Kenji sharpened the axe until its edge was as keen as a razor.

keen + edge/blade for physical sharpness

Common collocations
  • keen blade
  • keen edge
  • keen knife
  • keen point
Synonyms
  • sharp

    the everyday word for cutting ability; keen is more literary

  • razor-sharp

    emphasises an extremely fine edge

Antonyms

Grammar Patterns

keen + blade / edge / knife

Usage Note

Mainly used in formal, literary, or descriptive writing. In everyday speech, 'sharp' is far more common than 'keen' for describing cutting tools.

Common Mistakes

Pass me the keen knife.
Pass me the sharp knife.
In conversation, use 'sharp' instead of 'keen' for cutting tools.
Idioms

(as) keen as mustard

idiom

Very eager and enthusiastic about doing something.

Sara was as keen as mustard to start her new job.

The young volunteers were as keen as mustard on the project.

mad keen (on something/somebody)

idiom

Extremely enthusiastic about or very fond of someone or something.

Diego is mad keen on playing the guitar.

My sister is mad keen on that new singer.

keen — verb

keen — noun

Word family

  • keenly
    adverbB2
  • keenness
    nounC1
  • keener
    nounC1

Synonym discussion

Sense: adjective/1

These words all describe a strong positive interest in something, but they differ in intensity and context. Eager focuses on excitement about a future event and often carries a sense of impatience ('The children were eager to open their presents'). Enthusiastic conveys lively, energetic interest in an activity or idea that is already happening ('She gave an enthusiastic speech about the new recycling programme'). Avid suggests a very deep, almost consuming interest, typically in a long-term hobby or pursuit ('an avid reader who finishes three books a week'). Zealous is the strongest of the four, implying passionate commitment that can sometimes seem extreme or excessive ('a zealous campaigner who knocked on every door in the neighbourhood'). Keen sits between eager and enthusiastic, common in British English for describing a genuine, active interest that is less consuming than avid and less intense than zealous. Example: 'Matthew is a keen gardener but not a zealous one — he enjoys it without letting it take over his life.'

eager ↗enthusiastic ↗avid ↗zealous

Common collocations

Adverbs

  • particularly keen
  • especially keen
  • very keen
  • less keen

Prepositions

  • keen on
  • keen for

Etymology

Old EnglishMiddle EnglishEnglish

The adjective keen comes from Old English cēne, which originally meant 'bold, brave, or wise.' Over several centuries, its meaning shifted from personal courage to mental sharpness, and then from mental sharpness to the physical sharpness of a blade. The sense of 'eager' or 'enthusiastic' developed in the 1800s, especially in British English. Interestingly, the verb and noun senses (meaning 'to wail in grief' and 'a funeral lament') come from a completely different root — the Irish Gaelic word caoineadh, meaning 'to weep or wail.' These two separate words happen to share the same modern spelling and pronunciation, but they are historically unrelated.