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

• amigo
• buddy
• chum
• compadre
• comrade
• confidant
• confidante
• crony
• familiar
• friend
• intimate
• mate [chiefly British]
• musketeer
• pal

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

The reference is to Faust, but Reubens’s fraught relationship with his alter ego reminded me of another myth: that of the creator who loses control of his creation. —Michael Schulman, New Yorker, 23 May 2025

The actor has charm to spare, chemistry with leading lady Alexis Floyd and has given his alter ego a cocksure swagger that neatly straddles the line between confident and obnoxious. —Charlie Mason, TVLine, 18 May 2025

The book presents itself as a series of letters written by Vuong’s alter ego, Little Dog, to his mother, Rose, a mixed Vietnamese child of the Vietnam War who never learned to read. —Andrea Long Chu, Vulture, 6 May 2025

Lewis Pullman has already been confirmed to return as Bob (and, perhaps, his two alter egos, Sentry and the Void?) in 2026's Avengers: Doomsday, so his story isn't over after going through the emotional gauntlet in his debut MCU appearance. —Sydney Bucksbaum, EW.com, 12 May 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