The Collaborative International Dictionary of English v.0.48:

Corpulent \Cor"pu*lent\ (-p?-lent), a. [L. corpulentus, fr.
   corpus: cf. F. corpulent. See Corpse.]
   1. Very fat; obese.
      [1913 Webster]

   2. Solid; gross; opaque. [Obs.] --Holland.

   Syn: Stout; fleshy; bulky; obese. See Stout.
        [1913 Webster]

WordNet (r) 3.0 (2006):

corpulent
    adj 1: excessively fat; "a weighty man" [syn: corpulent,
           obese, weighty, rotund]

Moby Thesaurus II by Grady Ward, 1.0:

63 Moby Thesaurus words for "corpulent":
   adipose, beefy, big-bellied, bloated, blowzy, bosomy, brawny,
   broad-bodied, bulky, bullnecked, burly, buxom, chubby, chunky,
   coarse, crass, dense, distended, dumpy, fat, fattish, fleshy, full,
   full-bodied, gross, heavy, heavyset, hefty, hippy, imposing, lusty,
   massive, meaty, obese, overblown, overweight, paunchy, plump,
   podgy, portly, potbellied, pudgy, puffy, pursy, roly-poly, rotund,
   square, squat, squatty, stalwart, stocky, stout, strapping,
   swollen, thick, thick-bodied, thickset, three-dimensional,
   top-heavy, tubby, viscous, weighty, well-fed