1. An
obvious imitation, as a paste imitation to be substituted for a
real diamond. 2. A
substitute. 3. A double;
one who closely resembles another; hence, one easily mistaken for another. 4. (P)
An expert posing as an amateur.
"The Hatter’ll go down the line for you (will stand by you whatever happens), and he's a ringer with
a chiv (knife-wielder).”
- american underworld dictionary - 1950