a dark horse
成語所屬單字dark
a dark horse — 慣用語
1. a person who keeps their abilities, interests, or plans hidden from others, ofte
1.慣用語
釋義
黑馬（指實力意外出眾、令人驚喜的人）
a person who keeps their abilities, interests, or plans hidden from others, often surprising people by winning or doing well
例句
No one expected the new chef to win — she was a dark horse in the competition.
Hugo turned out to be a dark horse who could speak five languages fluently.