Synonyms of numbskull

1 Syllable
slow, ass, dim, dull, weak
2 Syllables
dummy, saphead, screwball, simple, dumbbell, jerked, backward, stupid, gorked, dumbo, dopey, touched, sappy, yo-yo, pinhead, dumdum, jerking
3 Syllables
birdbrained, slow-witted, retardo, subnormal, dim-witted, retarded, moronic, half-witted, opaque
4 Syllables
lamebrained, ignoramus, imbecile, defective, exceptional, feeble-minded, simple-minded
5 Syllables
underachieving