dark horse

1. 1.

   a political candidate who is not well known but could win unexpectedly

   Broadercampaigner
2. 2.

   a racehorse about which little is known

   Broaderracehorse

Questions about dark horse

What does dark horse mean?

dark horse means "a political candidate who is not well known but could win unexpectedly". That is the primary sense; the word has 2 in total, listed in full on this page.

Is dark horse a common word?

dark horse is banded "Uncommon" — turns up in careful writing rather than conversation. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.