Word forms: alter egos
COBUILD Advanced British English Dictionary1. countable nounYour alter ego is the other side of your personality from the one which people normally see.2. countable nounYou can describe the character that an actor usually plays on television or in films as his or her alter ego. ⇒ Barry Humphries's alter ego Dame Edna has taken the U.S. by storm.3. countable noun [usu poss N]An alter ego is a very close and intimate friend whose character is often the opposite of your own. ⇒ She is, first and foremost, her husband's alter ego.