W: (adj) incisive [Related to: incisiveness] (having or demonstrating ability to recognize or draw fine 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"
W: (adj) trenchant [Related to: trenchancy] (having keenness and forcefulness and penetration in thought, expression, or intellect) "searching insights"; "trenchant criticism"
W: (adj) trenchant [Related to: trenchancy] (clearly or sharply defined to the mind) "clear-cut evidence of tampering"; "Claudius was the first to invade Britain with distinct...intentions of conquest"; "trenchant distinctions between right and wrong"
S: (n) efficacy, efficaciousness (capacity or power to produce a desired effect) "concern about the safety and efficacy of the vaccine"
S: (n) power, powerfulness (possession of controlling influence) "the deterrent power of nuclear weapons"; "the power of his love saved her"; "his powerfulness was concealed by a gentle facade"