Noun
Lethal force, applied extrajudicially with the intent to kill.
Severe treatment.
Used other than figuratively or idiomatically: see extreme, prejudice.
Source: en.wiktionary.orgI'm interested in the fact that the less secure a man is, the more likely he is to have extreme prejudice. Clint Eastwood
Lyc-V is a jealous virus. It exterminates all other invaders with extreme prejudice. Ilona Andrews
He first appeared in the Season 9 episode Playing with Fire and terrorized NCIS until the Season 10 episode Extreme Prejudice when Gibbs finally killed him. Source: Internet