A bellyful is as much as you can stand of something. Had a bellyful of it, a bellyful of excuses, quite a bellyful.
It is nearly always used of things you have had enough of rather than of food — had a bellyful of his complaining — and it is informal and emphatic. The literal sense, a full stomach, is rare now. Note that the word is belly plus -ful, and that -ful making a noun of quantity is the same ending as in mouthful and handful.
1nounbellyfulAs much as you can stand of something.
“I've had a bellyful of your complaints, so either help or go home!”
bellyful is an amount endured.
Belly plus -ful. The -ful here makes a noun of quantity, as in handful and mouthful, rather than an adjective as in careful.
From belly + ful.
Etymology from Wiktionary, CC BY-SA
Practised in A Song of Ice and Fire