密みっ告こく者しゃ

noun

informer; snitch; betrayer

Refers to someone who secretly reports others' activities to authorities or an enemy; often carries a negative connotation similar to 'rat' or 'snitch'.

• 彼かれは警けい察さつの密みっ告こく者しゃだった。

  He was a police informer.

• 密みっ告こく者しゃが誰だれか分わからない。

  I don't know who the snitch is.