Blur

to obscure or sully (something) by smearing or with a smeary substance:
The windows were blurred with soot.
to obscure by making confused in form or outline; make indistinct:
The fog blurred the outline of the car.
to dim the perception or susceptibility of; make dull or insensible:
The blow on the head blurred his senses.
to become indistinct:
Everything blurred as she ran.
to make blurs.
a smudge or smear that obscures:
a blur of smoke.
a blurred condition; indistinctness:
They could see nothing in the foggy blur.
something seen indistinctly:
The ship appeared as a blur against the horizon.
Contemporary Examples

Brain Bleed: Why Michael Schumacher’s Helmet Wasn’t Enough Dr. Anand Veeravagu, MD, Tej Azad January 2, 2014
Party on in Pag: The Controversy on Croatia’s Hottest Island Kristin Vukovic August 24, 2013
A Hollywood Star’s Journey Through Meth Hell Anna David August 31, 2010
@PhantomState Raphael Magarik June 11, 2012
Your Horoscopes: May 15-21 Starsky + Cox May 13, 2011

Historical Examples

The Bostonians, Vol. I (of II) Henry James
The Black Bag Louis Joseph Vance
Transactions of the American Society of Civil Engineers, vol. LXX, Dec. 1910 Herbert M. Wilson
Mark Twain, A Biography, 1835-1910, Complete Albert Bigelow Paine
Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 3 Various

verb blurs, blurring, blurred
to make or become vague or less distinct: heat haze blurs the hills, education blurs class distinctions
to smear or smudge
(transitive) to make (the judgment, memory, or perception) less clear; dim
noun
something vague, hazy, or indistinct
a smear or smudge
n.
v.