dull
v.v. to make something less sharp, bright, or strong. You use this when a feeling becomes weaker or a blade loses its edge.
v. to reduce the intensity, sharpness, or brightness of something. Transitive or intransitive; often used metaphorically regarding physical pain or mental acuity.
The medicine helps to dull the sharp pain in my back.
Years of heavy use will eventually dull the blade of even the highest quality kitchen knife.
The architect chose a matte finish to dull the reflection of the midday sun against the glass facade, preventing a harsh glare for the neighbors.
From Middle English dull, dul (also dyll, dill, dwal), from Old English dol (“dull, foolish, erring, heretical; foolish, silly; presumptuous”), from Proto-West Germanic dol, from Proto-Germanic dulaz, from earlier dwulaz, a variant of dwalaz (“stunned, mad, foolish, misled”), from Proto-Indo-European dʰwel-, dʰewel- (“to dim, dull, cloud, make obscure, swirl, whirl”). Cognate with Scots dull, doll (“slow to understand or hear, deaf, dull”), North Frisian dol (“rash, unthinking, giddy, flippant”), Dutch dol (“crazy, mad, insane”), Low German dul, dol (“mad, silly, stupid, fatuous”), German toll (“crazy, mad, wild, fantastic”), Danish dval (“foolish, absurd”), Icelandic dulur (“secretive, silent”), West-Flemish dul (angry, furious).
The verb is often used with a direct object (transitive) but can also describe a quality fading over time (intransitive).