'Blotch' definitions:

Definition of 'blotch'

noun

An irregularly shaped spot [syn: blotch, splodge, splotch]

verb

Mark with spots or blotches of different color or shades of color as if stained [syn: mottle, streak, blotch]

From: GCIDE

Blotch \Blotch\, n. [Cf. OE. blacche in blacchepot blacking pot, akin to black, as bleach is akin to bleak. See Black, a., or cf. Blot a spot.]
1. A blot or spot, as of color or of ink; especially a large or irregular spot. Also Fig.; as, a moral blotch. [1913 Webster]
Spots and blotches . . . some red, others yellow. --Harvey. [1913 Webster]
2. (Med.) A large pustule, or a coarse eruption. [1913 Webster]
Foul scurf and blotches him defile. --Thomson. [1913 Webster]