The Collaborative International Dictionary of English v.0.48:

Pot-bellied \Pot"-bel`lied\, a.
   Having a protuberant belly, like the bottom of a pot.
   [1913 Webster]

WordNet (r) 3.0 (2006):

potbellied
    adj 1: having a large belly [syn: abdominous, paunchy,
           potbellied]

Moby Thesaurus II by Grady Ward, 1.0:

72 Moby Thesaurus words for "potbellied":
   adipose, bagging, baggy, ballooning, beefy, bellying, big-bellied,
   billowing, billowy, bloated, blowzy, bosomy, brawny, bulbose,
   bulbous, bulging, bumped, bumpy, bunched, bunchy, burly, buxom,
   chubby, chunky, corpulent, distended, dumpy, fat, fattish, fleshy,
   full, gross, heavyset, hefty, hillocky, hippy, hummocky, imposing,
   lusty, meaty, moutonnee, obese, overweight, paunchy, plump,
   pneumatic, podgy, portly, pouching, pudgy, puffy, pursy, roly-poly,
   rotund, rounded, square, squat, squatty, stalwart, stocky, stout,
   strapping, swelling, swollen, thick-bodied, thickset, top-heavy,
   tubby, verrucated, verrucose, warty, well-fed