Epigone reminded me of "gonnif" a Yiddish word for "thief"
mentioned but not defined by RhubarbCommando - I miss you, RC.

Ganef reminds me of motke der gonef (Mottke the Thief by Sholem Asch) and one of the characters he meets, shlomo der mamzer (Solomon the Bastard). Ganef is from Hebrew GNB 'thief' (ganabh) from the verb GNB 'to steal'.

Brian Jacques, in his Redwall series, has a character named, "Gonff". and yes, he's a thief. but a good thief.