Other forms: blurred, blurring, blurs
A blur is the smeared, unfocused look a thing has when it moves too fast or the camera misses focus. The cyclist in the photograph is a green blur; the signs go past the train window as one long streak of white.
As a verb it runs both ways: rain blurs the windscreen, and your own eyes blur when you have been reading too long. It works on ideas as well as edges, so a rule blurs the line between advice and instruction, and a film blurs fact and invention. Time gets the same treatment, and a week you barely slept through becomes a blur, meaning you cannot pull the days apart any more. Take off your glasses and the room blurs; the state is blurriness, and the adjective you want is blurry.
1nounblurA shape you cannot see clearly, because it is moving or out of focus.
“The kingfisher was a blue blur over the water.”
2nounstretchA stretch of time you cannot remember clearly.
“The first month with the baby is a blur.”
3verbunclearTo make something unclear to see, or to become unclear.
“Steam from the kettle blurred the window.”
4verbboundaryTo make a boundary or difference less sharp.
“Working from home blurs the line between the office and the sofa.”
blur is an unclear image.
Blur began as blurre, probably a reshaping of blear, the word still sitting inside bleary-eyed. Behind that stand Middle English bleren and Old English blerian, from Proto-Germanic blazjana, to make pale. The old idea was something washed out and weakened, which is what a blur does to an edge.
Proto-Germanic
*blazjaną — to make pale
Proto-West Germanic
*blaʀjan
Old English
*blerian
Middle English
bleren
English, today
blur
Built from
From earlier blurre, probably an alteration of blear, from Middle English bleren, from Old English blerian (attested in āblered (“made bare, made bald”)), from Proto-West Germanic blaʀjan, from Proto-Germanic blazjaną (“to make pale”), from Proto-Germanic blasaz (“pale”). Compare Scots blore, bloar (“to blur, cover with blots”), Low German bleeroged (“blear-eyed”). More at blear.
Etymology from Wiktionary, CC BY-SA