Q From Henrik Soderstrom in Spain: Any idea as to the origin of the expression spitting image?
A Several phrases have been used down the years to indicate that one person is the exact likeness of another: spitten image, spit and image, the very spit of, and dead spit for.
There are several theories about how these came about. The two most common suggest that our modern phrase is, via one or other of these forms, a corruption of spit and image. This contains the even older spit which existed by itself in phrases such as the last two above. Larry Horn, Professor of Linguistics at Yale, argues convincingly that the original form was actually spitten image, using the old dialectal past participle form of spit. He suggests that the phrase was reinterpreted when that form went out of use, first as spit ’n’ image and then as spit and image or spitting image.
But why spit? One view is that it’s the same as our usual meaning of liquid ejected from the mouth, perhaps suggesting that one person is as like the other as though he’d been spat out by him. But some writers make a connection here with seminal ejaculation, which may account for the phrase being used originally only of the son of a father.
Quite a different origin is suggested by other writers, who argue that spit is really an abbreviation of spirit, suggesting that someone is so similar to another as to be identical in mind as well as body. Professor Horn is sure that this supposed derivation is wrong.