- finely sharpened, as an edge; so shaped as to cut or pierce substances readily: a keen razor.
- sharp, piercing, or biting: a keen wind; keen satire.
- characterized by strength and distinctness of perception; extremely sensitive or responsive: keen eyes; keen ears.
- having or showing great mental penetration or acumen: keen reasoning; a keen mind.
- animated by or showing strong feeling or desire: keen competition.
- intense, as feeling or desire: keen ambition; keen jealousy.
- eager; interested; enthusiastic (often followed by about, on, etc., or an infinitive): She is really keen on going swimming.
- Slang. great; wonderful; marvelous.