The term DEAD RINGER (6 letters) is a lookalike of the phrase 'DEAD RINGER', which is an idiom used to describe someone or something that looks exactly like another person or thing. It is often used to describe a person who looks so similar to another that they could be mistaken for them. The phrase is thought to have originated in the late 19th century, when it was used to describe a horse that looked so much like another that it could be mistaken for it.