From Longman Dictionary of Contemporary Englishnarcnarc1 /nɑːk $ nɑːrk/ noun [countable] American English informal SCPMDDa police officer who deals with the problem of illegal drugs
Examples from the Corpus
narc• About half way into it, narcs start busting people.narcnarc2 verb [intransitive + on] American English informal to secretly tell the police about someone else’s criminal activities, especially activities involving illegal drugsOrigin narc1 (1900-2000) narcotic agent narc2 (1800-1900) Romany nak “nose” 