adjective

keen

/kiːn/ · say it: KEEN

eager and enthusiastic

In Emotions & Moods

In more detail

1. (adjective) very interested in something; eager

2. (adjective) having a sharp edge or point

3. (adjective) able to notice small differences; sharp (of senses or mind)

Examples

1. She is keen on learning new languages.
2. The knife has a keen blade.
3. He has keen eyesight and noticed the tiny error.

How to use keen

Keen as an adjective meaning 'eager' is common in British English and somewhat formal or literary in American English. It conveys genuine enthusiasm or intensity rather than casual interest. When meaning 'sharp' or 'acute,' it applies to senses, minds, or tools, often implying perceptiveness or effectiveness.

Common phrases

keen interest
keen on something
keen eye
keen sense
keen observer
keen to do something

Synonyms

eager · enthusiastic · avid · sharp · acute

Opposites

indifferent · dull · reluctant

Word family

keenly (adverb) · keenness (noun)

A common mistake

Learners sometimes confuse 'keen on' (interested in) with 'keen to' (eager to do); both are correct, but they take different grammatical structures—'keen on' takes a noun or gerund, while 'keen to' takes an infinitive.

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