WordWeb Online

1. Difficult to handle or use especially because of size or weight
   "a cumbersome piece of machinery";
   - cumbrous
    
2. Not elegant or graceful in expression
   "his cumbersome writing style";
   - awkward, clumsy, inapt, inept, ill-chosen, clunky [informal]

See also: infelicitous, unmanageable, unwieldy

Encyclopedia: Cumbersome