In its basic meaning, a dark horse is an unlikely winner of a competition of some kind. It refers to a person, and the image is taken from racing--a (nondescript?) contestant suddenly coming up from behind and crossing the finish line, seemingly from nowhere: "A dark horse candidate won the election"; "The recipient of the prize was a dark horse."[See related question in discussion section; couldn't get site to allow it.]
This from the folks at Wikipedia:The term began as horse racing parlance. A dark horse is a race horse that is not known to gamblers and thus is difficult to place betting odds on. Politically, the term was first applied to James K. Polk, a relatively unknown Tennessee Democrat who won the Democratic Party's 1844 presidential nomination over a host of better-known candidates. Polk won the nomination on the ninth ballot, and went on to win the presidential election.The general idea is that the 'dark horse' candidate is considered by those in the know to be unlikely to win, or at least unknown.In the political world, a dark horse candidate is someone who is not expected to win or even to do well in the contest.It means someone who is not expected to win.
Secretive/Shy/Has many private plans. Someone to keep an eye on, as they could surprise you in their abilities. In sporting terms a dark horse is often a team that would not necessarily be among the favourites, but could potentially do well, though not enough is known about them to be certain.
loose, or open "that jar isn't tight enough, its loose." or "he had a tight grip, but her hand had a loose grip."
loose change
A loose box is an enclosure for a horse where it can move around freely, whereas a stable is a structure where a horse is kept confined. Loose boxes are more open and allow for more movement, while stables are typically smaller and provide less space for the horse to roam.
The place in which a horse is kept is usually called a stable, stall, or loose box. And the place in which this box exists is called a yard or barn.
A stable or a loose box
A stable or loose box should be at least 4x4m (12 x 12ft), so that the horse has plenty of room.
Was Polk a "dark horse
The dark horse was beautiful.
Ride a dark horse in wilderness!
Hymns for a Dark Horse was created in 2007.
Dark Horse - novel - was created in 2008.
Dark Horse Records ended in 2004.
Dark Horse Records was created in 2002.
Dark Horse Comics was founded in 1986 by Mike Richardson in Milwaukie, Oregon.