To chide or rebuke someone gently; to reproach in order to correct their behavior (often written in kana).
母は子供が道路で遊んでいるのを見て、優しくたしなめた。
Seeing her child playing in the street, the mother gently chided him.
会議での失礼な発言を先輩がたしなめた。
A senior rebuked the rude comment made in the meeting.
彼女は冗談のつもりだったが、上司にたしなめられて気まずくなった。
She meant it as a joke, but she was reproved by her boss and it became awkward.