Longman Dictionary of Contemporary English
The Collaborative International Dictionary
front-runner \front-runner\ n. a competitor thought to be most likely to win.
Syn: favorite, favourite.
Douglas Harper's Etymology Dictionary
also frontrunner, of political candidates, 1908, American English, a metaphor from horse racing (where it is used by 1901 of a horse that runs best while in the lead).
Wiktionary
n. (alternative form of front runner English)
WordNet
Wikipedia
In American politics, a front-runner or frontrunner is a leader in an electoral race. While the front-runner in athletic events (the namesake of the political concept) is generally clear, a political front-runner, particularly in the U.S. presidential primary process, is less so; a potential nominee may lead in the polls, have the most name recognition, the most funds raised, or a combination of these. The front-runner is most often declared by the media who are following the race, and is written about in a different style than his or her challengers.
Usage examples of "front-runner".
The other, more complex, problem had to do with my natural out-front bias in favor of the McGovern candidacy -- which was not a problem at first, when George was such a hopeless underdog that his staffers saw no harm in talking frankly with any journalist who seemed friendly and interested -- but when he miraculously emerged as the front-runner I found myself in a very uncomfortable position.
He fanned the front-runners with hot lead, sending an unbroken string of brass hulls clattering against the wall to his right.
You will also experience a wildly selective generosity, the also-rans routinely overworked and underpaid, the front-runners smothered in celebrity purchases — jewels, furs, paintings, cars, and what Californians call a 'home'.
TrueBlood was definitely proving to be the front-runner among competing blood replacements.
Fearing a November steamrolling by Jeb Bush and the GOP, Buddy MacKay, the Democratic gubernatorial front-runner, recently asked Lawrence (a registered independent) to consider joining the ticket as lieutenant governor.