/ ˌdʒekl ən ˈhaɪd; NAmE / noun
[ sing. ] a person who is sometimes very pleasant ( Jekyll ) and sometimes very unpleasant ( Hyde ) or who leads two very separate lives
ORIGIN: From the story by Robert Louis Stevenson, Dr Jekyll and Mr Hyde , in which Dr Jekyll takes a drug which separates the good and bad sides of his personality into two characters. All the negative aspects go into the character of Mr Hyde.
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