I. ˈskəm-bəl transitive verb
( scum·bled ; scum·bling -b(ə-)liŋ)
Etymology: perhaps frequentative of scum (II)
Date: 1798
1.
a. : to make (as color or a painting) less brilliant by covering with a thin coat of opaque or semiopaque color applied with a nearly dry brush
b. : to apply (a color) in this manner
2. : to soften the lines or colors of (a drawing) by rubbing lightly
II. noun
Date: 1834
1. : the act or effect of scumbling
2. : a material used for scumbling