Synonyms for Ponderous (same or very similar meaning)
WordNet sense 1 (arousing no interest or attention or curiosity or excitement):
uninterestingWordNet sense 2 (slow and laborious because of weight):
lumberingWordNet sense 3 ((of movement) lacking ease or lightness):
heavy-footedWordNet sense 4 (of comparatively great physical weight or density):
heavyFrom the ODE community, based on WordNetadd/edit