a dirty &/or conniving &/or cheap person.
Referring to the Duddy Kravitz in mordecai richler's bestselling book. also can be a jew. usually is.
'did you see Jack look at her bum-oley? he is such a duddy kravitz!'
'what a duddy - he cheated me out of 5 cents.'
'stop being a duddy K and stick with your girlfriend.'