1. scumbling - Noun
2. scumbling - Verb
of Scumble
A mode of obtaining a softened effect, in painting and drawing, by the application of a thin layer of opaque color to the surface of a painting, or part of the surface, which is too bright in color, or which requires harmonizing.
In crayon drawing, the use of the stump.
The color so laid on. Also used figuratively.
Source: Webster's dictionary