Brit, Aus, NZ a police informer

a copper's nark

Aus, NZ an annoying person or thing

a whingeing or complaining person

Brit, Aus, NZ, informal (often + on) to spy or inform on people, esp for the police

to complain or whinge

informal (usu in passive) to offend or affront (somebody)

I was narked by her remark