WordWeb Online

1. Slow and laborious because of weight
   "ponderous prehistoric beasts"; "a ponderous yawn";
   - heavy, lumbering
    
2. Having great mass and weight and unwieldiness
   "a ponderous stone"; "a ponderous burden"; "ponderous weapons"
    
3. Laboured and dull
   "a ponderous speech"

See also: heavy, heavy-footed, lame, lameo [informal], meh [informal], uninspiring, uninteresting

Encyclopedia: Ponderous