He is very sharp, a quick thinker and swift with repartee.

他很机敏、思维敏捷并且能机智应答。

《柯林斯英汉双解大词典》

"Sharp" meant genuinely discerning, alert, acute rather than quick-witted or clever.

“Sharp”的意思是真正具有辨识力、警觉、敏锐，而不是机敏或聪明。

youdao

That would be welcome in itself—as a shrewd lawyer would no doubt be as quick to point out as a sharp economist.

它本身将是受欢迎的——正如一个狡猾律师必定会像一个尖锐的经济学家一样，被迅速地指出来。

youdao

He says Pakistani troops will have to launch quick, sharp and precise attacks in the area if they hope to prevail.

VOA: standard.2009.06.18

Instead of a quick, sharp downturn that quickly bounces into a booming recovery, capital and resources remain trapped producing things few want or bribed to remain idle.

FORBES: Why The Recession Recovery Remains Anemic

We love how quick and sharp 'fun' is, but in no way do we intend to give people the impression that we're going to walk into rooms doing back flips.

WSJ: Punctuation Nerds Stopped

He speaks a second language with his arm, hands, and fingers, using sharp, quick gestures for emphasis and clarity.

NEWYORKER: House of Cards