Thickskull

the dullwitted pair began to think of redeeming their turbans, and in spite of the entreaties of Agib, being very obstinate, as such thickskulls usually are, they went forth on that errand.

And how often do we hear persons stigmatized as 'numskulls' and 'thickskulls' and 'blockheads' — though why they should be block-heads, I know not […]