a dark horse

-prava nepoznanica; do jučer nepoznat javnosti

It’s difficult to predict who will win the prize—there are two or three dark horses in the tournament.
Everyone was surprised at the results of the election. The dark horse won.

1. (British & Australian humorous) a person who does not tell other people about their ideas or skills and who surprises people by doing something that they do not expect I didn’t know Linda had written a novel. She’s a bit of a dark horse, isn’t she?
2. a person who wins a race or competition although no one expected them to (sometimes + for ) 17-year-old Karen Pickering could also be a dark horse for (= she could win) a medal in the European Championships. (American)