WordNet sense 1 (drop sharply):

plummet

WordNet sense 2 (set (something or oneself) down with or as if with a noise):

plank, plop, plunk, flump, plonk, plump down, plunk down

WordNet sense 3 (make fat or plump):

fatten, plump out, fill out, fatten out, fatten up, flesh out

WordNet sense 4 (euphemisms for slightly fat):

chubby, embonpoint, zaftig, zoftig

WordNet sense 5 (having much flesh (especially fat)):

fat

WordNet sense 6 (give support (to) or make a choice (of) one out of a group or number):

go