Snitch
An inmate recruited by the administration to inform on fellow prisoners. "Snitches" often pretend to be nervous and difficult people, provoking fights and scandals. Guards burst into the cell to break up the fight, and – of course, by chance! – during the subsequent search, they discover something prohibited, such as a "shank" or preparations for an escape, etc. It is often difficult to prove malicious intent, and therefore prisoners are wary of those who like to show off their physical strength ("bulls") and instigators of conflict ("troublemakers"), seeing them as a threat to their situation.
Eldar Zeinalov

Your nickname: Witcher