2. (adj)acute, discriminating, incisive, keen, knifelike, penetrating, penetrative, piercing, sharp having or demonstrating ability to recognize or drawfine distinctions "an acute observer of politics and politicians"; "incisive comments"; "icy knifelike reasoning"; "as sharp and incisive as the stroke of a fang"; "penetrating insight"; "frequent penetrative observations"
4. (adj)bang-up, bully, corking, cracking, dandy, great, groovy, keen, neat, nifty, not bad(p), peachy, slap-up, swell, smashing very good "he did a bully job"; "a neat sports car"; "had a great time at the party"; "you look simply smashing"
5. (adj)cutting, keen, knifelike, piercing, stabbing, lancinate, lancinating painful as if caused by a sharpinstrument "a cutting wind"; "keen winds"; "knifelike cold"; "piercing knifelike pains"; "piercing cold"; "piercing criticism"; "a stabbing pain"; "lancinating pain"
6. (verb)keen having a sharp cutting edge or point "a keen blade"
7. (verb)lament, keen express grief verbally "we lamented the death of the child"