The crossword solution for the term 'Acts as an Informer' is 'SINGS'. This term is used to describe someone who provides information to the authorities, usually in exchange for some kind of reward. This type of informant is often used by law enforcement agencies to gain information about criminal activities. The term 'SINGS' is derived from the phrase 'singing like a canary', which is used to describe someone who is providing information to the authorities.