A person who is gorbellied is corpulent, with a protruding belly.
It seems probable that it derives from Old English gor or gore, meaning at first dung or dirt; in the sixteenth century it shifted sense to our modern one of blood that has been shed as a result of violence.
Gorbelly came along early in the sixteenth century, in a poem by John Skelton. The adjective followed soon after — Shakespeare used it in his Henry IV, Part One: “Hang ye, gorbellied knaves, are ye undone?” It dropped out of use in the nineteenth century, with one of the last users in a direct line from the ancients being Douglas Jerrold, who wrote “The gorbellied varlets, with mouths greasy with the goods of cheated worth.”
These days it appears only rarely, being a word resurrected to give a sense of another age in historical fiction or fantasy, as in Harry Turtledove’s alternate history, Ruled Britannia, in which the English failed to defeat the Armada in 1588 and in which the delightful scene-setting opening line is “Two Spanish soldiers swaggered up Tower Street toward William Shakespeare.” Turtledove writes later, “‘Consumption catch thee, thou gorbellied knave!’ a boatman yelled.”
To save anyone pointing it out, it’s also in James Joyce’s Ulysses.