dark horse

someone in a race that is considered very unlikely to win (especially a political race); political candidate who is nominated unexpectedly; racehorse in respect of which little is known

A dark horse is a political candidate who is nominated unexpectedly, or any other underdog.Dark Horse may also refer to:Dark Horse (astronomy), a large dark nebulaDark Horse (album), one of George Harrison's solo albums"Dark Horse" (song), a song by George HarrisonDark Horse (film), a 2005 movie by Dagur KáriDark Horse Comics, a comic book publisherDark Horse Records, a recording company owned by George HarrisonDark Horse Brewery, a brewpub in Marshall, MichiganDark Horse (1992 film), a 1992 movie by David HemmingsThe Dark Horse (film), a 1932 movie by Alfred E. GreenDark Horse (novel), a novel by Fletcher KnebelThe nickname of the 3rd Battalion 5th MarinesThe name of the College of William & Mary's men's ultimate (frisbee) team for the 2002 open season, and 2003 college season.
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This article describes dark horse candidates. For other uses, see Dark Horse. A dark horse candidate is one who is nominated unexpectedly, without previously having been discussed or considered as a likely choice. Often a dark horse is selected as a compromise when other, more prominent candidates' factions cannot come to an agreement. This metaphoric expression originally alluded to an unknown horse winning a race and was so used in a novel by Benjamin Disraeli (The Young Duke, 1831).
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Noun
1. a political candidate who is not well known but could win unexpectedly
(hypernym) campaigner, candidate, nominee
2. a racehorse about which little is known
(hypernym) racehorse, race horse, bangtail

the competitor that could surprise us and win The dark horse in the World Cup is Ireland. They could win it all.

Synonyms and related words:
also-ran, aspirant, baby kisser, bare possibility, candidate, defeated candidate, dud, enigma, favorite son, fighting chance, frontier, frontiers of knowledge, gambling chance, hardly a chance, hopeful, hundred-to-one shot, improbability, lame duck, little chance, little opportunity, long odds, long shot, matter of ignorance, mystery, n, off chance, office seeker, outside chance, political hopeful, poor bet, poor lookout, poor possibility, poor prospect, presidential timber, puzzle, remote possibility, riddle, running mate, sealed book, slim chance, small chance, stalking-horse, terra incognita, the incalculable, the strange, the unfamiliar, the unknowable, the unknown, unexplored ground, unexplored territory, unknown quantity, unlikelihood, x, z,