nark

Etymology 1

Uncertain. Perhaps from Angloromani nok (“nose”), from Romani nakh, from Sauraseni Prakrit 𑀡𑀓𑁆𑀓 (ṇakka), ultimately a doublet of nose.

noun

1. (Britain, slang) A police spy or informer.
   So I went and laid down on the grass. While laying there I piped a reeler whom I knew. He had a nark (a policeman's spy) with him. So I went and looked about for my two pals, and told them to look out for F. and his nark. 1879 October, J[ohn] W[illiam] Horsley, “Autobiography of a Thief in Thieves’ Language”, in Macmillan’s Magazine, volume XL, number 240, London: Macmillan and Co.[…], →OCLC, page 505, column 1
2. (Australia, slang) An unpleasant person, especially one who makes things difficult for others.

verb

1. (transitive, thieves' cant) To watch; to observe.
2. (intransitive, slang) To serve or behave as a spy or informer.
   “If you nark on me, I’ll rip your arms off,” said Tim to his brother, as he passed him a joint.
3. (transitive, slang) To annoy or irritate.
   It really narks me when people smoke in restaurants.
4. (intransitive, slang) To complain.
   He narks in my ear all day, moaning about his problems.
5. (transitive, slang, often imperative) To stop.
   Nark it! I hear someone coming!

Etymology 2

See narc.

noun

1. Alternative form of narc (narcotics officer).