'Dull' in the Bible
"On the next seventh day, the priest is to examine him again. If the skin rash didn't become dull and it didn't spread in the skin, then the priest is to pronounce him clean: it's a scab. He is to wash his clothes and be clean.
If the priest undertakes an examination, but there's no white hair in it and it's not more extensive than skin deep, but it's dull, then the priest is to isolate him for seven days.
But if the priest examines it and discovers that there's no bright area or white hair, or if he discovers that it's not more extensive than skin deep and it's dull, then the priest is to isolate him for seven days.
But if the bright spot remains in place, doesn't spread in the skin, and it's dull, it's the swelling of the burned area. The priest is to declare him clean, since it's the scar from a burn."
when the priest examines it and finds that there is a light or dull white patch of skin on the body, it's a harmless skin eruption that has spread on the skin. The person is clean."
"If the priest examines the item and determines that the contagion has become dull after it has been washed, tear it away from the garment, leather, woven material, or knitted material.
Pay attention, you dull ones among the crowds! You fools! Will you ever become wise?
Dull the mind of this people, deafen their ears, and blind their eyes. By doing so, they won't see with their eyes, hear with their ears, understand with their minds, turn back, and be healed."
"See, the LORD's hand is not too short to save, nor are his ears too dull to hear.