smudge

smudge (http://definr.com/smudge)

     n 1: a smoky fire to drive away insects
     2: a blemish made by dirt; "he had a smudge on his cheek" [syn:
         spot, blot, daub, smear, smirch, slur]
     v : make a smudge on; soil by smudging [syn: smear, blur, smutch]