Synonyms for Potbellied:

adj.

fat (adjective)
big, corpulent, obese, paunchy, plump, rotund, stout.
obese (adjective)
bloated, beerbellied.
overweight (adjective)
fat.
round (adjective)
bulbous, corpulent, rotund, round, rounded, spherical.
tubby (adjective)
chubby, overweight.

n.

fat (noun)
ample, big, buxom, chubby, obese, overweight, plump, stout, tubby.
potbellied (noun)
abdominous, fat, paunchy.

Other synonyms:

Other relevant words:
abdominous, bloated, buxom, chubby, fat, obese, overweight, paunchy, plump, stout, tubby.