spit and image » spitting image
Originally entered by xerby, who commented:
Just a phrase, “spitting image”, I’d heard for about forty years. And then one day someone on the radio said “spit and image” which immediately made more sense to me. In the first we could easily visualize a boy picking up his father’s bad habits(spitting…like mothers don’t spit), or if you’ve ever seen a boy walking with his dad you’d see the same gait(as well as image). In the second instance, “spit” infers a more visceral, biological, connection.
And, of course, the visual “image” stays as part of the phrase.
Most major dictionaries report that _spitting image_ is an alteration of _spit and image_. In an article in American Speech, however, Larry Horn argues that the expression was originally _spitten image_ (_spitten_ being a now-archaic dialectal form of the past participle of _spit_), and that both _spit and image_ and _spitting image_ are later reinterpretations. (The _American Speech_ link requires a subscription to Project Muse — see also Michael Quinion’s summary at World Wide Words).