blot / blät/ • n. a dark mark or stain, typically one made by ink, paint, or dirt: an ink blot. ∎  a shameful act or quality that tarnishes an otherwise good character or reputation: the only blot on an otherwise clean campaign.• v. (blot·ted, blot·ting) [tr.] 1. dry (a wet surface or substance) using an absorbent material: Guy blotted his face with a dust rag.2. mark or stain (something): [as adj.] (blotted) the writing was messy and blotted. ∎  tarnish the good character or reputation of: the turmoil blotted his memory of the school.3. (blot something out) cover writing or pictures with ink or paint so that they cannot be seen. ∎  obscure a view: a dust shield blotting out the sun. ∎  obliterate or disregard something painful in one's memory or existence: the concentration necessary to her job blotted out all the feelings.

blot spot, stain. XIV. The distribution of the earliest exx. is consistent with a Scand. orig., but no suitable form is known; cf., however, Icel. blettr blot, stain, Da. dial. blat spot, blot.
Hence blot vb. spot, stain. XV (blotting-paper XVI).