blotch

Short definition from Wiktionary

Noun

1. 1
   An uneven patch of color or discoloration.
2. 2
   An irregularly shaped area.
3. 3
   Imperfection; blemish on one’s reputation, stain.
4. 4
   Any of various crop diseases that cause the plant to form spots.
5. 5
   A bright or dark spot on old film caused by dirt and loss of the gelatin covering the film, due to age and poor film quality.
6. 6
   A dark spot on the skin; a pustule.
7. 7
   Blotting paper.

Verb

1. 1
   To mark with blotches.
2. 2
   To develop blotches, to become blotchy.