subs. (old).A fat, round-bellied man; a pot-belly, a CORPORATION (q.v.). Hence TUN-BELLIED = paunchy, very corpulent, bellied like a tun: cf. TUN-GREAT (quot. 1383) = with a circumference of the size of a tun.
[1383. CHAUCER, The Canterbury Tales, The Knights Tale, 1996. Every piler the temple to sustene was TONNE-GRET.]
1550. LEVER, Sermons [ARBER], 119 [T. L. KINGTON-OLIPHANT, The New English, i. 524. There are the phrases greedygut and TUNNE BELYED].
1651. CARTWRIGHT, The Royall Slave, i., 1. Some drunken Hymne I warrant you towards now, in the prayse of their great huge, rowling, TUNBELLYED god Bacchus as they call him.
1687. SEDLEY, Bellamira, iii. 1. I must have no TUN-BELLYD Rogues, that fright Chair-men from the house.
d. 1704. T. BROWN, Works, iii. 152. He has swore to her by all that is good and sacred never to forgive the presumptuous wretch that should think irreverently of a double chin and a TUN BELLY.