For those Mooseketeers who are not fluent in Yiddish, "goniff" means a dishonest person.    From Wordnik.com.  [Archive 2005-05-01] Reference

"That goniff who should be doing time, chopping rocks, making license plates, somehow slipped out of his apartment confinement and he's treating himself to a shore dinner.".    From Wordnik.com.  [The New Yorker] Reference

They used Yiddish words such as tineff for ` shoddy goods, 'goniff for ` thief,' mumser for an ` unpleasant person '(usually the head merchandise buyer), zu viel gelt for ` too much money,' schlock for.    From Wordnik.com.  [VERBATIM: The Language Quarterly Vol XIII No 3] Reference

I'd rather you didn't hear me negotiating for money with this goniff, since it might tarnish the bright image you have of me as a sweet and demure person. ".    From Wordnik.com.  [Tek Money]

He's both a war hero and a goniff.    From Wordnik.com.  [""You... can be a millionaire... and never pay taxes! You can be a millionaire... and never pay taxes!"] Reference