The Collaborative International Dictionary of English v.0.48:

Ponderous \Pon"der*ous\, a. [L. ponderosus, from pondus, -eris,
   a weight: cf. F. pond['e]reux. See Ponder.]
   1. Very heavy; weighty; as, a ponderous shield; a ponderous
      load; the ponderous elephant.
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            The sepulcher . . .
            Hath oped his ponderous and marble jaws. --Shak.
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   2. Important; momentous; forcible. "Your more ponderous and
      settled project." --Shak.
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   3. Heavy; dull; wanting; lightless or spirit; as, a ponderous
      style; a ponderous joke.
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   Ponderous spar (Min.), heavy spar, or barytes. See
      Barite.
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