be the spit of (someone)

To look exactly like or bear a very strong resemblance to someone. Primarily heard in Ireland. Wow, you are just the spit of your mother! I was about to call you by her name. That guy over there is the spit of someone I went to secondary school with. Pete? Oh, I'm sorry, Larry. From the side, you are the spit of Pete from Accounting!

be the spit (or the dead spit) of

look exactly like. informal

The full form of the phrase is be the spit and image of , perhaps coming from the idea of a person apparently being formed from the spit of another, so great is the similarity between them. This fuller form also lies behind the expression spitting image .