Twists & Turns of Phrase
To look a gift horse in the mouth is to fail to appreciate the generosity someone has shown you.
Now as a city girl, I’ve never received a horse, and if I did I’m pretty sure looking in its mouth wouldn’t be my first impulse. So who would look a gift horse in the mouth, and why would it show them to be ungrateful?
Origins: It turns out that people can tell a lot about the age and the health of a horse by looking at its teeth, so it makes sense that someone in the market for a new steed would take a look at those pearly whites before buying one. But if someone’s just given you a horse and the first thing you do is check its chompers…well, I can see how that’s a bit rude. It’s a lot like tossing the unread greeting card over your shoulder in your haste to see how many zeros are on your birthday cheque, isn’t it?
History: According to the OED, this turn of phrase has been around since at least 1546 when John Heywood recorded it as follows in A dialogue conteinyng the nomber in effect of all the prouerbes in the Englishe tongue: No man ought to looke a geuen hors in the mouth.