The term 'INFORM ON SOMEONE' can be summarized by two crossword solutions: SNITCH (6 letters) and SHOP (4 letters). To 'SNITCH' means to secretly tell someone in authority about the wrongdoings of another person. It is often seen as a negative term, as it implies betrayal. To 'SHOP' someone means to provide information to the authorities about a person's illegal activities. This term is also seen as negative, as it implies that someone is trying to get another person in trouble.