When someone is said to look like someone else, should they be referred to as “the splitting image”  or “the spitting image?”
A recent slideshow posted on Time features actors who have portrayed famous people in biopics. If you were going to write the headline, would you have chosen the phrase “splitting image”  or “spitting image?”
This is one of those questions that you probably already knew the answer to…at least until I asked. But then, once you’re given a choice of the two nearly-identical terms, it’s easy to stop and think too much about it.
The key to making the right choice involves knowing the reason we use the right one.
When you see them side by side, splitting might seem the obvious choice, implying the two were split from the same whole to make two identical units. Consider identical twins, after all, who develop from just one zygote that will then split and form two embryos.
Despite the greater amount of sense splitting might make, spitting is the correct answer.
The Phrase Finder suggests the phrase came into being as a morph from the original spit and image or, perhaps, spitten image. It notes that George Farquhar wrote the line, “Poor child! he’s as like his own dadda as if he were spit out of his mouth,” in his play “Love and a bottle”  in 1689.
Charming, isn’t it?
But the Grammarist suggests a much older origin for the phrase spit and image, the predecessor of spitting image, pointing to the Biblical story of Adam’s creation, in which God created the first man from “spit and mud.”
So now you know!
By the way, when you check out the slideshow from Time, you see that they correctly chose “Spitting Image” for their headline.