inform on - definition and synonyms

phrasal verb [transitive]
present tense
I/you/we/theyinform on
he/she/itinforms on
present participleinforming on
past tenseinformed on
past participleinformed on

or inform against

  1. inform on/against someone to secretly give the police or someone in authority information about someone

    The rule has always been that you don’t inform on a friend.

See also main entry: inform