from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Slang A clumsy person.
- n. Slang A stupid person; a dolt.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A clumsy or stupid person; an oaf.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. (Yiddish) a clumsy dolt
Yiddish klots, from Middle High German kloz, block, lump, from Old High German.(American Heritage® Dictionary of the English Language, Fourth Edition)
From the Yiddish קלאָץ (klots, "wooden beam"), cognate with German Klotz ("block, lump"). (Wiktionary)