A dead ringer

a very close likeness, like a twin Chad is a dead ringer for Mel Gibson. They look like twins.

a very close likeness, like a twin Chad is a dead ringer for Mel Gibson. They look like twins.

Meaning
An exact duplicate.
Origin
A ringer is a horse substituted for another to defraud the bookies. Dead here means exact rather than lifeless. The Victorian practise of fitting wires and bells into coffins to allow people who were buried alive to call for rescue is unrelated. Such devices certainly did exist but weren't the source of the phrase.