Synonyms for Nark (same or very similar meaning)
WordNet sense 1 (an informer or spy working for the police):
copper's narkWordNet sense 2 (a lawman concerned with narcotics violations):
narc, narcotics agentWordNet sense 3 (cause annoyance in; disturb, especially by minor irritations):
annoy, bother, chafe, devil, gravel, irritate, nettle, rag, rile, vex, get at, get toFrom the ODE community, based on WordNetadd/edit