Dead ringer

From Fresh Dictionary

English

Noun

dead ringer

1. ((idiomatic{{#if:|, {{{2}}}{{#if:|, {{{3}}}{{#if:|, {{{4}}}{{#if:|, {{{5}}}{{#if:|, {{{6}}}{{#if:|, {{{7}}}{{#if:|, {{{8}}}{{#if:|, {{{9}}}}}}}}}}}}}}}}}}})) Someone or something that very closely resembles another; someone or something easily mistaken for another.

   He is a dead ringer for his grandfather at that age.