To be jealous of; to envy or begrudge someone (often with a sense of resentment).
彼は同僚の昇進を妬んでいるようだ。
He seems to be jealous of his colleague's promotion.
妹の才能を妬む気持ちを抑えられなかった。
I couldn't suppress my jealousy of my sister's talent.
人の成功を妬んでも何もいいことはない。
Nothing good comes from envying someone else's success.