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

Brighton are a real Jekyll and Hyde side at the moment, but I always feel they will do well at home - they have only lost once there this season.

From BBC • Dec. 18, 2025

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

Brentford are like Jekyll and Hyde, depending on where you play them.

From BBC • Nov. 21, 2024

But it’s the Jekyll and Hyde manner those shots have been compiled — something McCann alluded to — that’s been perplexing in its inconsistency.

From Seattle Times • Nov. 12, 2023

It is like being taught by Jekyll and Hyde.

From "The Absolutely True Diary of a Part-Time Indian" by Sherman Alexie