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.
   Drape, Trappings.]
   1. A kind of thick woolen cloth of a dun, or dull brownish
      yellow, or dull gray, color; -- called also drabcloth.
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   2. A dull brownish yellow or dull gray color.
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