dumm·kopf 
(dmkôf′, -kôpf′, dŭm-)
(dmkôf′, -kôpf′, dŭm-)n.
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, ultimately from Late Latin cuppa; see CUP).]