The phrase "dark horse" often refers to someone or something that is unexpected to succeed or emerge as a winner. Synonyms for this expression include "underdog", "long shot", "surprise winner", "unexpected champion", "outsider", "unpredicted contender", "rising star", and "unexpected hero". These all indicate a degree of surprise and unpredictability in a given situation. They are often used to describe a competitor or candidate that is not considered a frontrunner, but who ultimately leads or outperforms the other contenders. The term "dark horse" is derived from horse racing, where a horse whose abilities are unknown may surprise everyone with a victory.