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.

---

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

---

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.

---

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

Rather, like “Jekyll and Hyde, the two share a memory and even a wardrobe.”

From Los Angeles Times

After watching Rangers' Jekyll and Hyde performances as a pundit and club ambassador all season, Ferguson has now witnessed them from pitchside.

From BBC

They make Jekyll and Hyde look uncomplicated; at times pure thoroughbreds, the Frankel of rugby and, at other times, self-destructive, the Devon Loch of the age.

From BBC

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

From Los Angeles Times