incisive

adj.

[1]	keen , acute , discriminating , sharp , acute , keen , knifelike , piercing , perspicacious , penetrating , penetrative , perceptive , percipient , piercing , sharp , penetrating , trenchant , canny , shrewd
[2]	sarcastic , biting , mordant , cutting , caustic , sardonic , ironic(al) , sharp , acid , tart , acrid , acrimonious , bitter , acerbic , cynical , stinging , critical