Source : Webster's Revised Unabridged Dictionary (1913)

Cumbrous \Cum"brous\ (k?m"br?s), a.
   1. Rendering action or motion difficult or toilsome; serving
      to obstruct or hinder; burdensome; clogging.

            He sunk beneath the cumbrous weight.  --Swift.

            That cumbrousand unwieldy style which disfigures
            English composition so extensively.   --De Quincey.

   2. Giving trouble; vexatious. [Obs.]

            A clud of cumbrous gnats.             --Spenser.
      -- {Cum"brous*ly}, adv. -- {Cum"brous*ness}, n.