Klutz

google

ref

1930s: from Yiddish klots ‘wooden block’.

wiktionary

ref

From Yiddish קלאָץ‎ (klots, literally “wooden beam”); cognate to German Klotz(“block, lump”).

etymonline

ref

klutz (n.)

1967, American English, from Yiddish klots "clumsy person, blockhead," literally "block, lump," from Middle High German klotz "lump, ball." Compare German klotz "boor, clod," literally "wooden block" (see clot (n.)).