Suffix attached to nouns to express that the amount is sufficient or excessive. Often used in negative or critical contexts. Compare with たくさん, which is a standalone adverb/noun.
See also: たくさん
That's enough. Any more is too much worry.
His stories are full of boasting; I'm tired of listening.
Derived from たくさん (many, a lot) with rendaku voicing. The suffix usage is relatively modern and colloquial.