Other forms: duller, dulled, dullest
Something dull has no brightness and no life in it. A grey November sky, a dull knife that squashes the tomato instead of cutting it, a lesson so dull you start counting ceiling tiles.
It covers colours (a dull brown), sounds (a dull thud from the flat above), light, weather and pain — a dull ache in the shoulder is the slow kind, the opposite of a sharp one. Said of a person it is an insult: dull means boring, and it once meant slow to learn, which is why it still stings. As a verb it means to make something weaker: a drink to dull the pain, years that dull a memory. Dullness is the noun and dully the adverb. 'Never a dull moment' is what you say when things keep going wrong and nobody has sat down all day.
1adjectiveshineNot bright; without shine or strong colour.
“The paint had gone a dull grey.”
2adjectivedullBoring; with nothing in it to hold your interest.
“It was a dull meeting about parking.”
3adjectivebluntBlunt; not sharp enough to cut well.
“A dull blade tears the bread instead of slicing it.”
4adjectivemuffledMuffled or low, of a sound; slow and steady rather than sharp, of a pain.
“There was a dull thud as the door swung shut.”
5verbbrightTo make something less sharp, bright or strong.
“The medicine dulls the pain enough to let him sleep.”
Too few real examples of this word to estimate which sense is commonest.
Dull started out meaning foolish. Old English dol was stupid or mistaken, from a Germanic word *dwalaz for someone stunned or misled, and behind that a root *dʰwel- meaning to dim, cloud or make obscure. The picture is a mind or a day with fog in it — and from there the word slid across to a dull knife, a dull sky and a dull afternoon.
Proto-Indo-European
*dʰwel-
Proto-Germanic
*dulaz
Proto-West Germanic
*dol
Old English
dol — dull, foolish, erring, heretical; foolish, silly; presumptuous
Middle English
dull
English, today
dull
Built from
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”), frr 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).
Etymology from Wiktionary, CC BY-SA