dummkopf

Dictionary: dumm·kopf   (dʊm'kôf', -kôpf', dŭm'-)

A stupid person; a dolt.

[German : dumm, dumb (from Middle High German tump, tumb, from Old High German tumb) + Kopf, head (from Middle High German, cup, cranium, from Old High German, cup, from Late Latin cuppa).]

noun

A mentally dull person: blockhead, chump¹, clod, dolt, dullard, dummy, dunce, numskull, thickhead. Slang dimwit, dumbbell, dumbo. See ability/inability.