keen

¹ American  

[keen] / kin /

adjective

keener, keenest

1. finely sharpened, as an edge; so shaped as to cut or pierce substances readily.

   a keen razor.

   Antonyms:

   dull

2. sharp, piercing, or biting.

   a keen wind;

   keen satire.

   Synonyms:

   caustic, bitter, cutting

3. characterized by strength and distinctness of perception; extremely sensitive or responsive.

   keen eyes;

   keen ears.

   Synonyms:

   acute, penetrating, piercing

4. having or showing great mental penetration or acumen.

   keen reasoning;

   a keen mind.

   Synonyms:

   clever, shrewd, sagacious, astute, acute, discerning

   Antonyms:

   obtuse, dull

5. animated by or showing strong feeling or desire.

   keen competition.

6. intense, as feeling or desire.

   keen ambition;

   keen jealousy.

7. eager; interested; enthusiastic; (often followed by about, on, etc., or an infinitive).

   She is really keen on going swimming.

   Synonyms:

   fervid, earnest

8. Older Slang. great; wonderful; marvelous.

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keen ² American  

[keen] / kin /

noun

1. a wailing lament for the dead.

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verb (used without object)

1. to wail in lamentation for the dead.

verb (used with object)

1. to mourn for by or with such keening or wailing.

   keening his mother while kneeling at her grave.

keen ¹ British  

/ kiːn /

adjective

1. eager or enthusiastic

2. fond (of); devoted (to)

   keen on a girl

   keen on golf

3. intellectually acute

   a keen wit

4. (of sight, smell, hearing, etc) capable of recognizing fine distinctions

5. having a sharp cutting edge or point

6. extremely cold and penetrating

   a keen wind

7. intense or strong

   a keen desire

8. extremely low so as to be competitive

   keen prices

9. slang very good

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keen ² British  

/ kiːn /

verb

1. to lament the dead

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noun

1. a dirge or lament for the dead

Usage

What does keen mean? Keen commonly means eager, interested, or enthusiastic. This sense of the word is often followed by about or on and the particular interest, as in He’s very keen on music. More generally, keen means sharp, intense, or strong. It can be used to mean sharp in a literal way, as in a keen blade. It can also be used in several figurative ways. A keen sense of smell is one that’s very strong and perceptive. A keen intellect is one that’s sharp in the sense of being mentally strong. A keen desire is an intense one. A keen satire and a keen wind are both piercing and biting—they both sting. The word keen can also be used as a slang term meaning wonderful or splendid, and this is how it’s used in the phrase peachy keen, which is used as an informal and playful way to describe something as excellent or wonderful. Example: He showed keen jealousy over my keen knife.

Related Words

See sharp. See avid.

Other Word Forms

• keener noun
• keenly adverb
• keenness noun

Etymology

Origin of keen¹

First recorded before 900; 1930–35 keen ¹ for def. 8; Middle English kene, Old English cēne; cognate with German kühn, Old High German chuoni “bold,” Old Norse kœnn “wise, skillful”

Origin of keen²

First recorded in 1780–90 for the verb; from Irish caoin-, stem of caoinim “(I) lament”; noun derivative of the verb

Explanation

If you have a keen interest in something, you are really, really into it. Keen is an adjective that describes something that is intense, sharp, or focused. The word keen comes from the Old English word cene that translates to "bold and brave" and while the spelling is now really different, the sounds are similar. Variations of keen as being "bold" and "strong" show up in other languages, but only English has the meaning of "sharp" — relating to "an edge or blade." Keen has a lot of close — and brutal — synonyms, such as caustic, cutting, piercing, and penetrating. It can also be used as a verb to mean "express grief or pain out loud."

Example Sentences

Political leaders are often keen to be seen with AI's top names, Thibout added, if only to help get some of their huge development spending for their states or regions.

From Barron's • Apr. 25, 2026

Over the years I spent at the club, I was always very keen to invite older Stoke favourites in to watch training on a Thursday, and then have lunch with the players.

From BBC • Apr. 24, 2026

He was particularly keen on, and became friends with, Chuck Berry.

From Los Angeles Times • Apr. 24, 2026

It was one of many episodes that showed his decisiveness, keen understanding of Apple’s culture and products, and how to get things done inside the company, the people said.

From The Wall Street Journal • Apr. 21, 2026

I was back in the world with a clear head and a keen vision of just how talented I really was.

From "Me Talk Pretty One Day" by David Sedaris

Related Words

• anxious
• ardent
• avid
• eager
• fervent
• fierce
• impatient
• intense