alter ego

/ˌˈɔltə ˌrigoʊ/

/ˈɔltə ˈigəʊ/

Other forms: alter egos

Your alter ego is a person to whom you are so close that he almost seems like an essential part of you, and who understands your unique perspective on the world.

You can use the noun alter ego to describe your very best friend, the person who knows you better than anyone else. The Latin meaning of alter ego is "other self," and it was used by the ancient Roman statesman and philosopher Cicero in a letter to his friend and adviser, Atticus: "You are a second brother to me, an alter ego to whom I can tell everything."

Definitions of alter ego

1. noun

   a very close and trusted friend who seems almost a part of yourself
   type of:

   friend

   a person you know well and regard with affection and trust