adj. 1 (of a person, desire, or interest) eager, ardent (a keen sportsman). 2 (foll. by on) much attracted by; fond of or enthusiastic about. 3 (of the senses) sharp; highly sensitive. 4 intellectually acute. 5 a having a sharp edge or point. b (of an edge etc.) sharp. 6 (of a sound, light, etc.) penetrating, vivid, strong. 7 (of a wind, frost, etc.) piercingly cold. 8 (of a pain etc.) acute, bitter. 9 Brit. (of a price) competitive. 10 colloq. excellent. keenly adv. keenness n.
[ OE cene f. Gmc ]