1711, from tar (n.1) + brush (n.1). To have a touch of the tarbrush "have a dash of African ancestry visible in the skin tone" (1796) was "a term of contempt from the West Indies" [Century Dictionary].
a viscous liquid, Old English teoru, teru "tar, bitumen, resin, gum," literally "the pitch of (certain kinds of) trees," from Proto-Germanic *terw- (source also of Old Norse tjara, Old Frisian tera, Middle Dutch tar, Dutch teer, German Teer), probably a derivation of *trewo-, from PIE *derw-, variant of root *deru- "be firm, solid, steadfast," with specialized senses "wood, tree" and derivatives referring to objects made of wood.
Tar baby "a sticky problem," also a derogatory term for "black person," is from an 1881 "Uncle Remus" story by Joel Chandler Harris. Tarheel for "North Carolina resident" first recorded 1864, probably from the gummy resin of pine woods. Tar water, an infusion of tar in cold water, was popular as a remedy from c. 1740 through late 18c.
"instrument consisting of flexible material (bristles, hair, etc.) attached to a handle or stock," late 14c., "dust-sweeper, a brush for sweeping," from Old French broisse, broce "a brush" (13c., Modern French brosse), perhaps from Vulgar Latin *bruscia "a bunch of new shoots" (used to sweep away dust), perhaps from Proto-Germanic *bruskaz "underbrush." Compare brush (n.2). As an instrument for applying paint, late 15c.; as an instrument for playing drums, 1927. Meaning "an application of a brush" is from 1822.
<a href="https://www.etymonline.com/word/tarbrush">Etymology of tarbrush by etymonline</a>
Harper, D. (n.d.). Etymology of tarbrush. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/tarbrush