NUMSKULL
dunce, dunderhead, numskull, blockhead, bonehead, lunkhead, hammerhead, knucklehead, loggerhead, muttonhead, shithead, dumbass, fuckhead
(noun) a stupid person; these words are used to express a low opinion of someone’s intelligence
Source: WordNet® 3.1
Etymology
Noun
numskull (plural numskulls)
(pejorative) A dunce, mentally dull or stupid person.
(pejorative) A person who refuses to learn or grow mentally.
A traditional name for a fool who serves as the butt of jokes about stupidity.
Synonyms
• See also fool
Source: Wiktionary
Num"skull`, n. Etym: [Numb + skull.]
Definition: A dunce; a dolt; a stupid fellow. [Colloq.]
They have talked like numskulls. Arbuthnot.
Source: Webster’s Unabridged Dictionary 1913 Edition