agent provocateur
agent provocateur (ay-j[schwa]nt pr[schwa]-vok-[schwa]-t[schwa]rora-zhawn praw-vaw-k[schwa]-tuur), n. 1. An undercover agent who instigates or participates in a crime, often by in-filtrating a group suspected of illegal conduct, to expose and punish criminal activity. 2. A person who entraps another, or entices another to break the law, and then informs against the other as a lawbreaker.