<p><strong>Adjective</strong></p><ul><li>(comparative) Keener</li><li>(superlative) Keenest</li><li>Finely sharpened, as an edge; so shaped as to cut or pierce substances readily: a keen razor.</li><li>Antonyms: Dull</li><li>Sharp, piercing, or biting: a keen wind; keen satire.</li><li>Synonyms: Caustic, bitter, cutting</li><li>Characterized by strength and distinctness of perception; extremely sensitive or responsive: keen eyes; keen ears.</li><li>Synonyms: Acute, penetrating, piercing</li><li>Having or showing great mental penetration or acumen: keen reasoning; a keen mind.</li><li>Synonyms: Clever, shrewd, sagacious, astute, acute, discerning</li><li>Antonyms: Obtuse, dull</li><li>Animated by or showing strong feeling or desire: keen competition.</li><li>Intense, as feeling or desire: keen ambition; keen jealousy.</li><li>Eager; interested; enthusiastic; (often followed by about, on, etc., or an infinitive): She is really keen on going swimming.</li><li>Synonyms: Fervid, earnest</li><li>Older Slang: Great; wonderful; marvelous.</li></ul>