dark horse

American  

noun

dark horses plural

1. a racehorse, competitor, etc., about whom little is known or who unexpectedly wins.

2. a candidate who is unexpectedly nominated at a political convention.

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dark horse British  

noun

1. a competitor in a race or contest about whom little is known; an unknown

2. a person who reveals little about himself or his activities, esp one who has unexpected talents or abilities

3. politics a candidate who is unexpectedly nominated or elected

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dark horse Cultural  

1. An unexpected winner. In politics, a dark horse is a candidate for office considered unlikely to receive his or her party's nomination, but who might be nominated if party leaders cannot agree on a better candidate.

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dark horse Idioms  

1. A little known, unexpectedly successful entrant, as in You never can tell—some dark horse may come along and win a Senate seat. 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). It soon began to be transferred to political candidates, among the first of whom was James K. Polk. He won the 1844 Democratic Presidential nomination on the eighth ballot and went on to win the election.

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Other Word Forms

Noun Inflected Forms

• dark horses
  plural

Etymology

Origin of dark horse

First recorded in 1825–35

Example Sentences

Norway may have been touted by many as this World Cup's dark horse but their impressive progress still feels like they have exceeded expectations.

From BBC • Jul. 10, 2026

In a tune-up against Senegal, the Americans won 3-2 against a country seen as a World Cup dark horse as Pulisic snapped a five-month goalless drought.

From The Wall Street Journal • Jun. 12, 2026

Now, on his main-draw debut on the Paris clay, Jodar has emerged as a dark horse for the Coupe des Mousquetaires.

From BBC • Jun. 1, 2026

That angst was a big reason why 64-year-old Sanae Takaichi surged from dark horse to Japan’s first female prime minister in October.

From Barron's • Jan. 8, 2026

He found the dark horse in the night and stood caressing the warm skin, thick bristly mane, feeding sugar, talking.

From "The Killer Angels: The Classic Novel of the Civil War" by Michael Shaara

Related Words

• also-ran
• long shot
• sleeper
• underdog