Keen, 1) sharp: “k. teeth,” Sonn. 19, 3. As II, 7, 177. “whips,” Meas. II, 4, 101. “edge,” LLL I, 1, 6. V, 2, 256. “knife,” Merch. IV, 1, 124. Mcb. I, 5, 53. “arrows,” As III, 5, 31. “sword,” Mcb. V, 8, 10. Metaphorically, of persons: “let us be k., and rather cut a little,” Meas. II, 1, 5.
2) bitter, acrimonious: “thy k. conceit,” LLL V, 2, 399; cf. LLL V, 2, 399 “this k. mockery,” Mids. II, 2, 123. “when she's angry, she's k. and shrewd,” III, 2, 323. “some satire, k. and critical,” V, 54. “my k. curses,” John III, 1, 182. “this k. encounter of our wits,” R3 I, 2, 115. “you are k., my lord,” Hml. III, 2, 258 (quibbling).
3) eager: “k. appetite,” Lucr. 9. Sonn. 118, 1. Merch. II, 6, 9. “advice is often seen by blunting us to make our wits more k.” Compl. 161. “so k. and greedy to confound a man,” Merch. III, 2, 278. “a dull fighter and a k. guest,” H4A IV, 2, 86. “assailed with fortune fierce and k.” Per. V, 3, 88.