Someone who offers up information voluntarily to assist in the arrest or disciplinary action of another. In the penal system such individuals are placed in whats known as "check-in" or Protective Custody to avoid the physical harm which usually accompanies their underhanded and cowardly tactics.
Damn can't believe Gabe is a snitch bitch! He tried to get me busted because he's a hater. That's lower than a cop! At least cops get paid to try to get people busted!