narc [nahrk] / nark [nahrk]
1. Slang. A government agent or detective charged with the enforcement of laws restricting the use of narcotics.
2. Slang. A police informant.
3. A stool pigeon, a tipster, an informant.
4. To act as an informant to the police or to report a crime and/or criminal activities.
EX. "I am appalled by the accusations against our new compatriot, Steve. He is hardly a narc. Look! He is wearing a Music Band shirt. No narc would know about Music Band. They're so underground."