gift [ME] A word related to give [OE] and deriving from Old Norse gipt. Don’t look a gift horse in the mouth is a proverb that goes back to the 16th century (in the form do not look a given horse in the mouth), but it can be found even earlier in a 5th-century Latin version in the writings of St Jerome. A common way of estimating a horse’s age is to look at the state of its teeth, so if you were buying a horse you might want to have a good look into its mouth first. If someone gave you a horse as a present, it might seem ungrateful to start checking how old it was.