drab (n.)
1680s, "color of natural, undyed cloth," from Middle French drap (see drape (n.)). Figurative sense is c.1880. Apparently not related to earlier word meaning "a dirty, untidy woman" (1510s), "a prostitute" (1520s), which seems to be connected with Irish drabog, Gaelic drabag "dirty woman," and perhaps with Low German drabbe "dirt." Ultimately perhaps from PIE *dher- (1) "to make muddy." Meaning "small, petty debt" (the sense in dribs and drabs) is 1828, of uncertain connection to the other senses.