don't be a narc
Usually means don't be a grass when used in a social setting. This can either be for illegal drug use or any type of controversial behaviour. Similar to how a brother or sister grasses you in for doing something bad to your parents.
Narc often means narcotics officer amongst gangs.
Narc often means narcotics officer amongst gangs.
'Don't be a narc bro, elbowing Jimmy in the face was funny anyway he's a dick'