expression, godan verb (-ru)
jump on someone's verbal mistake; trip someone up verbally; find fault with what someone says
Idiomatic expression; used when someone seizes on a minor slip in another person's words to criticize or embarrass them. Often implies nitpicking or unfair fault-finding.
See also: 揚げ足を取る
彼はすぐ人の揚げ足を取るから、話しにくい。
He's always jumping on people's verbal mistakes, so it's hard to talk to him.
Please stop making remarks that trip people up.