Jekyll and Hyde

American  

[jek-uhl, jee-kuhl] / ˈdʒɛk əl, ˈdʒi kəl /

noun

1. a person marked by dual personality, one aspect of which is good and the other bad.

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Jekyll and Hyde British  

/ ˈdʒɛkəl, haɪd /

noun

1. 1. a person with two distinct personalities, one good, the other evil

   2. ( as modifier )

      a Jekyll-and-Hyde personality

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Jekyll and Hyde Idioms  

1. A personality alternating between good and evil behavior, as in You never know whether Bob will be a Jekyll or a Hyde. This expression comes from Robert Louis Stevenson's The Strange Case of Dr. Jekyll and Mr. Hyde (1886). Also see lead a double life.

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Etymology

Origin of Jekyll and Hyde

After the protagonist of Robert Louis Stevenson's The Strange Case of Dr. Jekyll and Mr. Hyde (1886)

Example Sentences

"David could be a bit of a Jekyll and Hyde character," said John Duff, a local councillor and former police superintendent, who was born and grew up in Aberfeldy.

From BBC • Feb. 25, 2026

Over its long history, hormone replacement therapy for women in menopause has been the Jekyll and Hyde of medications.

From Los Angeles Times • Jan. 21, 2025

England were a bit Jekyll and Hyde in an easy pool and then had a quarter-final against a Fiji team that has not really fired.

From BBC • Oct. 18, 2023

These personas sit atop her shoulders, Rivera said, battling it out like a Boricua Jekyll and Hyde.

From New York Times • Apr. 19, 2023

Gradually, however, like Jekyll and Hyde, one personality began to predominate.

From "Kaffir Boy: An Autobiography" by Mark Mathabane