My new colleague is a dead ringer (Doppelgänger) for our disgraced former CFO. It has led to some strange looks being exchanged in the hallways at work.
For a non-native English speaker, there are no clues about what this idiom means to be found in the words themselves. So, what is the origin of this phrase? A ‚ringer‘ is a horse substituted for another of similar looking horse to trick the bookies (Buchmacher). ‚Dead‘ has more than one meaning besides „not alive“. The meaning here is „exact“ or „precise“. This is can be found in many phrases; like ‚dead shot‘ (Volltreffer) and ‚dead centre‘ (genaue Mitte).
So, ‚dead ringer‘ is the same as ‚exact duplicate‘.