To flatly reject or spurn a request or proposal; to refuse sharply. Somewhat colloquial with a strong tone of refusal.
彼は給料アップの交渉を突っぱねられて、驚いた表情を浮かべた。
He was flatly turned down when negotiating a raise and looked surprised.
会社はその要求を一度も検討せずに突っぱねた。
The company dismissed the demand without even considering it.
親の勧めを突っぱねて、自分の道を選んだ。
He rejected his parents' advice and chose his own path.