I guess I can tell a gentleman from a con man or a flimflammer when I meet him.
A confidence man; cheater; swindler: an expert flimflammer who worked up crime's ladder (1880s+)
: a flimflam game/ flimflam man
: Don't fall for that flimflam
To cheat or swindle; defraud; bamboozle, con: We've been flimflammed/ He talked like some hick begging to be flimflammed (1538+)