A term sometimes used to refer to conmen, due to the stereotype of a slick-looking man in a
three piece suit. The term isn't gender-specific, but most people seem to use it to indicate a
conman (versus the usually more feminine term "
grifter").
Three piece also implies that the conman (or woman) was high-class among the stealing trade, or acted and dressed as a rich person to inspire the confidence necessary to the con.
"I
invested my money, but it turned out my
broker was a
three piece."
"I gave that three piece every penny I had and he stole all of it!"