'Dull' in the Bible

then the priest shall look; and, behold, if the bright spots in the skin of their flesh be of a dull white, it is a tetter, it hath broken out in the skin; he is clean.

For this people's heart is waxed gross, And their ears are dull of hearing, And their eyes they have closed; Lest haply they should perceive with their eyes, And hear with their ears, And understand with their heart, And should turn again, And I should heal them.

For this people's heart is waxed gross, And their ears are dull of hearing, And their eyes they have closed; Lest, haply they should perceive with their eyes, And hear with their ears, And understand with their heart, And should turn again, And I should heal them.

Of whom we have many things to say, and hard of interpretation, seeing ye are become dull of hearing.