Eager; vehement; as hungry curs too keen at the sport. The sheep were so keen on the acorns-- .

Eager; sharp; as a keen appetite.

Sharp; having a very fine edge; as a keen razor, or a razor with a keen edge. We say a keen edge, but a sharp point.

Piercing; penetrating; severe; applied to cold or to wind; as a keen wind; the cold is very keen.

Bitter; piercing; acrimonious; as keen satire or sarcasm. Good father cardinal, cry thou amen, To my keen curses.

To sharpen.