1 general:: Phrase(s): inform on someone to tell the authorities about someone; to tattle on someone. • I am going to have to inform on you. • Liz informed on Ken to their mother., Phrase(s): inform someone on someone; to tattle (on someone) (to someone). • I will inform the teacher on you! • Billy informed his mother on Bobby.
McGrawhill's American Idioms And Phrasal Verbs