Entries linking to unhorse
More or less confused with un- (1) through similarity in the notions of "negation" and "reversal;" an adjective such as unlocked might represent "not locked" (un- (1)) or the past tense of unlock (un- (2)).
late Old English horsian "to provide with a horse or horses," from horse (n.). Related: Horsed; horsing. Sense of "to play excessive jokes on" is by 1893, mostly in formation horse around (1928), perhaps from horse-play, or from earlier nautical jargon use of the verb in reference to men, "drive or urge to work unfairly and tyrannically" (1867). But also consider the vulgar expressions arsing about (1660s), arsing around (1922).
[A] favorite pastime for many men is to "horse" or guy a friend who has shown himself susceptible to ridicule or fun making. "Horsing" is extremely wholesome mental discipline for over sensitive or super-conceited young men. "Horsing" always implies a joke at another's expense. As to how it came into use there is no satisfactory theory to offer. [Yale Literary Magazine, December 1893]
As a verb, horse also meant "to mount on horseback" (early 14c., horsen), "to spank" as one does a horse to get it to go (1825), also "to copulate, mount" (as a stallion does a mare), hence figuratively, of men, "copulate with" a woman (mid-15c.).