numbskull (n.)

c. 1400, nome, "deprived of motion or feeling, powerless to feel or act," literally "taken, seized," from past participle of nimen "to take, seize," from Old English niman "to take, catch, grasp" (from PIE root *nem- "assign, allot; take"). The unetymological -b (to conform to comb, limb, etc.) appeared 17c. The notion is of being "taken" with palsy, shock, and especially cold. Figurative use is from 1560s.

"cranium, the bony framework of the head," c. 1200, sculle, probably from Old Norse skalli "a bald head, skull," a general Scandinavian word (compare Swedish skulle, Norwegian skult), itself probably related to Old English scealu "husk" (see shell (n.)).

But early prominence in southwestern texts suggests rather origin from a Dutch or Low German cognate (such as Dutch schol "turf, piece of ice," but the sense of "head bone framework" is wanting). Derivation from Old French escuelle "bowl" seems unlikely on grounds of sound and sense. An Old English word for skull was heafod-bolla. Latin cranium also is glossed at least once in Middle English as braynpanne.