1. (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"
2. (adj)incisive suitable for cutting or piercing "incisive teeth"