spitting image 
noun informal
The exact double of (another person or thing): she’s the spitting image of her mum...
- Jake is the spitting image of his long-lost twin brother, who was killed on a recent mission.
- Not only was the name an exact match-up, he also was the spitting image of the man in the courtroom sketch that had been provided in the book.
- I was a spitting image of mum and he couldn't stand to see me there, her exact replica, and not have her there herself.
Origin
Late 19th century: originally as the spit of or the spit and image of; perhaps from the idea of a person apparently being formed from the spit of another, so great is the similarity between them.