穴あなを穿うがつ

expression, godan verb (-tsu)

find someone's weak spot; hit a sore point

Idiomatic use: to pinpoint a hidden weakness or sensitive point in an argument or person. The literal meaning 'to drill a hole' is rarely used in modern Japanese; the phrase is almost always figurative.

• 彼かれの指し摘てきはまさに穴あなを穿うがつものだった。

  His remark really hit a sore point.

• その質しつ問もんは相あい手ての矛む盾じゅんを穴あなを穿うがつように突ついた。

  The question sharply exposed the opponent's contradiction.