Narc

Noun

 * 1)  A narcotics squad police officer.
 * 2)   – A person who notifies authorities of illicit activity, betraying someone in the process.

Verb

 * 1)   – to inform authorities of the illicit actions of others that one has knowledge of as an insider
 * “If you narc on me, I’ll rip your arms off”, said Tim to his little brother, as he passed him a cigarette.
 * 1)  To suffer from impaired judgment due to nitrogen narcosis (e.g. while scuba diving).

Synonyms

 * rat out
 * tattle

Thesaurus
Bow Street runner, FBI, FBI agent, Federal, G-man, MP, Secret Service, Sherlock Holmes, T-man, bailiff, beadle, beagle, bear witness against, betray, betrayer, blab, blabber, blabberer, blabbermouth, blow the whistle, bound bailiff, captain, catchpole, chief of police, commissioner, constable, delator, deputy, deputy sheriff, detective, fed, federal, fink, flic, gendarme, government man, hotel detective, house detective, house dick, inform against, inform on, informer, inquiry agent, inspector, investigator, lictor, lieutenant, mace-bearer, marshal, mounted policeman, officer, operative, patrolman, peace officer, peach, peacher, plainclothesman, police captain, police commissioner, police constable, police detective, police inspector, police matron, police officer, police sergeant, policeman, policewoman, portreeve, private detective, private investigator, rat, reeve, revenuer, roundsman, sell out, sergeant, sergeant at arms, sheriff, sleuth, snitch, snitch on, snitcher, spy, squeal, squealer, stool, stool pigeon, stoolie, store detective, superintendent, talebearer, tattle, tattler, tattletale, tell on, telltale, testify against, tipstaff, tipstaves, treasury agent, trooper, turn informer, whistle-blower

Alternative forms

 * nark

Etymology
Abbreviation of "narcotics officer" (narcotics sense only)

Noun

 * Romanian: turnător

Verb

 * Romanian: a turna

Anagrams

 * cran
 * cRNA
 * NRCA