DARK HORSE, DAWN ON (SOMEONE), DAYS ARE NUMBERED (SOMEONE’S/SOMETHING’S): American English Idioms #53
DARK HORSE Originally, the phrase “dark horse” was used to describe a candidate in an election who entered relatively unknown or unexpected. In recent years, the term has been used to describe a person or thing that is unexpectedly successful. A dark horse is an unexpected candidate for victory or success. It can also refer…