A DARK HORSE


Meaning of A DARK HORSE in English

1.

( BrE ) a person who does not tell other people much about their life, and who surprises other people by having interesting qualities

2.

a person taking part in a race, etc. who surprises everyone by winning

Oxford Advanced Learner's English Dictionary.      Оксфордский английский словарь для изучающик язык на продвинутом уровне.