blemish, mar, defect - a mark or flaw that spoils the appearance of something (especially on a person's body); "a facial blemish"

blotch, splodge, splotch - an irregularly shaped spot

fingermark, fingerprint - a smudge made by a (dirty) finger

inkblot - a blot made with ink

error, mistake, fault - a wrong action attributable to bad judgment or ignorance or inattention; "he made a bad mistake"; "she was quick to point out my errors"; "I could understand his English in spite of his grammatical faults"

imbibe, soak up, sop up, suck up, absorb, suck, take up, take in, draw - take in, also metaphorically; "The sponge absorbs water well"; "She drew strength from the minister's words"

stain - produce or leave stains; "Red wine stains the table cloth"

change surface - undergo or cause to undergo a change in the surface

splotch - blotch or spot

maculate, tarnish, defile, sully, stain - make dirty or spotty, as by exposure to air; also used metaphorically; "The silver was tarnished by the long exposure to the air"; "Her reputation was sullied after the affair with a married man"

bespeckle, speckle - mark with small spots; "speckle the wall with tiny yellow spots"

bespatter, spatter - spot, splash, or soil; "The baby spattered the bib with food"