Penetrating, clear, and sharp, as in operation or expression: an incisive mind; incisive comments.
derivatives
in·císive·ly
adverb
in·císive·ness
noun
synonyms:
incisive, trenchant, biting, cutting, crisp These adjectives refer to keenness and forcefulness of thought, expression, or intellect. Incisive and trenchant suggest penetration to the heart of a subject and clear, sharp, and vigorous expression: an incisive report; trenchant wit. Biting and cutting often have a sarcastic or sardonic quality capable of wounding or stinging: “Biting remarks revealed her attitude of contempt” (D.H. Lawrence) “He can say the driest, most cutting things in the quietest of tones” (Charlotte Brontë) Crisp suggests clarity, conciseness, and briskness: a crisp retort.
The American Heritage® Dictionary of the English Language, Fourth Edition