The phrase 'Dead Ringer' is used to indicate that one person or thing is exactly like another.
Example of Use: “Jennifer is a dead ringer for her grandmother.”
The expression 'dead ringer' comes from American horse racing and originated at the end of the 19th century, when a horse that would be raced under a false name and pedigree was called a ringer. The word 'dead' in this expression refers not to lifelessness, but to “precise” or “exact.”