narc (n.)youdaoicibaDictYouDict[narc 词源字典]
1967 (earlier narco, 1960), American English slang, shortened form of narcotics agent. Had been used 1955 for narcotics hospital, 1958 for narcotics addict. Sense and spelling tending to merge with older but unrelated nark (q.v.).[narc etymology, narc origin, 英语词源]