be the spit of
be the dead spit of (someone)
To look exactly like someone else. Primarily heard in UK. Wow, you are just the dead spit of your mother! I was about to call you by her name.
be the spit of (someone)
To look exactly like or bear a very strong resemblance to one. 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.
be the spit (or the dead spit) oflook 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 .