The Collaborative International Dictionary of English v.0.48:
Drab \Drab\, n. [F. drap cloth: LL. drappus, trapus, perh.
orig., a firm, solid stuff, cf. F. draper to drape, also to
full cloth; prob. of German origin; cf. Icel. drepa to beat,
strike, AS. drepan, G. treffen; perh. akin to E. drub. Cf.
1. A kind of thick woolen cloth of a dun, or dull brownish
yellow, or dull gray, color; -- called also drabcloth.
2. A dull brownish yellow or dull gray color.