Ponderous, a.
Etymology: [L. ponderosus, from pondus, -eris, a weight: cf. F. pondéreux. See Ponder.]
1. Very heavy; weighty; as, a ponderous shield; a ponderous load; the ponderous elephant. The sepulcher . . . Hath oped his ponderous and marble jaws. Shak.
2. Important; momentous; forcible. "Your more ponderous and settled project." Shak.
3. Heavy; dull; wanting; lightless or spirit; as, a ponderous style; a ponderous joke. Ponderous spar (Min.), heavy spar, or barytes. See Barite.
Shades of meaning
Fernald lists ponderous only as an antonym, under airy.
He lists it without comment; the entries above explain its neighbors.
Synonyms
none given