Meaning: You can offer help or advice to somebody, but you can't force him or her to accept it.

Origin: Recorded in Old English Homilies from 1175, it seems that this is the oldest English proverb that's still in use (there are other proverbs that are older, but were originally spoken in a different language). Granted, the English used then looks nothing like the language we use now:

"Hwa is thet mei thet hors wettrien the him self nule drinken." (Who can give water to the horse that will not drink of its own accord?)

Meaning: To continue arguing after the matter is settled.

Origin: Beating a dead horse is obviously a pointless activity, just like pushing a matter that nobody else wants to discuss. The first known use of the phrase was when the British politician John Bright was speaking about the futility of trying to get Parliament to care about the Reform Act of 1867. In a speech, Bright said trying to get them interested "would be like trying to flog a dead horse to make it pull a load."

Some scholars believe the idiom came from the slang term "dead horse," which was used in the 17th century to mean work that was already paid for.

Meaning: Hold on a minute/ be patient.

Origin: As one might guess, the idiom comes from the way a horse rider or driver pulls on the reins to "hold his horse." In Homer's The Iliad, Antilochus drives his chariot recklessly during a race and Menelaus tells him to "hold his horses." The phrase showed up in the figurative sense in September 1844 in the New Orleans Picayune.

"Oh, hold your hosses, Squire. There's no use gettin' riled, no how." ("Hoss" was slang for "horse").

The modern version of the phrase showed up in the New York Times on March 26, 1855 in an article about the steamship George Law.

"That we shall be able to pay after a time is without a doubt, but just at this moment ¡°it can¡¯t be did,¡± so ¡°hold your horses.¡±

Meaning: Be grateful for any gifts you receive and don't obsess over their value.

Origin: A horse's teeth is a good indicator of his age, so somebody who "looked a gift horse in the mouth" would be assessing the horse's value. That's obviously a rather rude thing to do in the presence of the gift giver.

Versions of the proverb have been around since at least 400 AD. A Latin text of St. Jerome, The Letter to the Ephesians, contains the phrase Noli equi dentes inspicere donati, which translates as "Never inspect the teeth of a given horse."

Meaning: From a reliable source (such as somebody in authority or the primary source).

Origin: The first use of this phrase appears to have been in the Syracuse Herald in May 1913:

"I got a tip yesterday, and if it wasn't straight from the horse's mouth it was jolly well the next thing to it."

Many people believe this idiom came from the world of horse racing, as the above quote would indicate. Another theory about the origin of this phrase goes along with the "gift horse." If somebody was buying a horse, s/he could check the horse's teeth to make sure the health records given by the seller were accurate. If everything checked out, the facts would have come "straight from the horse's mouth."

Meaning: Stop acting like you're better than everybody else.

Origin: Back in the Middle Ages, when important people appeared in public, they did so riding large expensive horses. In other words, high horses. People started using the phrase figuratively in the 18th century. In more recent years, it's been used in reference to people who think they're powerful, important, or elite rather than those who truly are.

Meaning: Something other than expected or planned.

Origin: Most people are familiar with this idiom due to the scene in The Wizard of Oz, in which the "horse of a different color" literally changes colors. Of course, the phrase usually doesn't refer to horses.

Some people credit Shakespeare's Twelfth Night as the source of this phrase. Maria says, "My purpose is, indeed, a horse of that colour," when telling Sir Toby and Sir Andrew about her idea to get revenge on Malvolio. Others say it came from horse racing. Someone may bet on one horse only to be surprised that "a horse of a different color" wins the race.