Dull, v. t. [imp. & p. p.Duller (?); p. pr. & vb. n.Dulling.] 1. To deprive of sharpness of edge or point. “This... dulled their swords.” Bacon.
Borrowing dulls the edge of husbandry. Shak.
2. To make dull, stupid, or sluggish; to stupefy, as the senses, the feelings, the perceptions, and the like.
Those she has
Will stupefy and dull the sense a while. Shak.
Use and custom have so dulled our eyes. Trench.
3. To render dim or obscure; to sully; to tarnish. “Dulls the mirror.” Bacon.
4. To deprive of liveliness or activity; to render heavy; to make inert; to depress; to weary; to sadden.
Attention of mind... wasted or dulled through continuance. Hooker.