A colloquial expression meaning to do or emit something once. Depending on context, it can mean to fire a shot or deliver a single blow, or colloquially to let out a fart.
試合で彼は一発放って逆転のゴールを決めた。
In the match he took one shot and scored the game-changing goal.
講演で鋭い一発を放つコメントが聴衆の注目を集めた。
A sharp remark made during the lecture grabbed the audience's attention.
彼は緊張していて、ついおならを一発放ってしまった。
He was nervous and accidentally let out a fart.