nudnik
An irritating, nagging person; a boring pest of a person who makes constant or persistent demands or criticisms. Originating from the Yiddish verb nuden A: "Tom? Can I speak to you for a moment?" B: "Sheesh, what does that nudnik want now?" Quit being a nudnik and leave me alone already! I'll do the dishes a little later!
nudnik
(ˈnʊdnɪk) n. a bore; a pest; a crank. (From Russian via Yiddish. Also a term of address.) Tell that nudnik to stay away from here. He is such a pest.