alter ego

noun

al·​ter ego ˌȯl-tər-ˈē-(ˌ)gō 

also

-ˈe-(ˌ)gō 

plural alter egos

1

: a second self or different version of oneself: such as

a

: a trusted friend

b

: the opposite side of a personality

Clark Kent and his alter ego Superman

c

: counterpart sense 3

a fictional character that is the author's alter ego

2

law : a person or entity vicariously liable for another (such as an agent)

… because the Cuban bank had not physically participated in the expropriation, it could not be considered an alter ego of the Government in the context of the Citibank case.

—The New York Times

Did you know?

In Latin, alter ego literally means "second I". An alter ego can be thought of as a person's clone or second self. A professional alter ego might be a trusted aide who knows exactly what the boss wants done. A personal alter ego might be a close friend who is almost like a twin. Alter ego can also refer to the second, hidden side of one's own self. In Robert Louis Stevenson's classic The Strange Case of Doctor Jekyll and Mr. Hyde, Dr. Jekyll is a good-hearted, honorable man; but after taking a potion, his alter ego, the loathsome and diabolical Mr. Hyde, takes over his personality.

Synonyms

• friend
• buddy

Examples of alter ego in a Sentence

a trusted adviser who is the President's alter ego

over the years the state's other senator became his alter ego as well as his political ally

Recent Examples on the Web

Reubens had purposely foregrounded his alter ego Pee Wee and hid himself from the public spotlight, making appearances on TV shows like The Tonight Show with David Letterman as the character. —Matt Shaw, Forbes.com, 28 June 2025

The possibly confused, wound-up Holmes is a world away from Mister Romantic, the long-running alter ego behind Reilly’s new album of romance ballads, What’s Not To Love. —Gil Kaufman, Billboard, 17 June 2025

Some of those adjectives could also describe Ackles’ longtime TV alter ego, from The CW’s Supernatural. —Matt Webb Mitovich, TVLine, 17 June 2025

The reader of Dykes to Watch Out For will recognize Alison as a new, unimproved version of Bechdel’s comic-strip alter ego, Mo: a total drag who rails against the capitalist war machine but is too self-absorbed to picket a homophobic business. —Andrea Long Chu, Vulture, 16 June 2025

Word History

Etymology

borrowed from Latin alter egō "close friend," literally "other I," perhaps as translation of Greek állos egṓ, héteros egṓ

Note: Cf. M. Tullius cicero, Letters to Atticus 3.15.4.: "… me enim ipsum multo magis accuso, deinde te quasi me alterum et simul meae culpae socium quaero." ("I am reproaching myself far more than you, and if I do reproach you it is as my alter ego; also I am looking for someone to share the blame" - translation by D. R. Shackleton Bailey.)

First Known Use

1537, in the meaning defined at sense 1

Rhymes for alter ego

• impetigo
• loligo

Kids Definition

alter ego

noun

al·​ter ego ˌȯl-tər-ˈē-gō 

1

: a trusted friend or personal representative

2

: the opposite side of a personality

Legal Definition

alter ego

noun

al·​ter ego ˈȯl-tər-ˈē-gō 

: second self

especially : a person or entity vicariously liable for another (as an agent)

had the officer been the alter ego of the corporation

—J. J. White and R. S. Summers

compare instrumentality

Note: The concept of a legal alter ego is used primarily to hold the controlling parties of a corporation personally liable instead of limiting liability to the corporate entity.

Etymology

Latin, literally, second I