English version

nark in Crime topic

From Longman Dictionary of Contemporary Englishnarknark /nɑːk $ nɑːrk/ noun [countable] informal especially British English  SCCSCPsomeone who is friendly with criminals and who secretly tells the police about their activities syn informer
Examples from the Corpus
narkI know if he is a thief, right, a beggar, a pimp, a copper's nark.