Great boast, small roast.

The proverb contrasts an impressive claim with a disappointing result. The small roast makes the gap between what was promised and what was provided easy to picture.

It criticizes boasting that exceeds what someone can deliver. Its point is not simply that the result is modest, but that the earlier talk made it sound much greater.

Use it to comment on a conspicuous promise or boast followed by a meager outcome, especially when the contrast invites a dry, critical response. It can refer to an actual offering or, more broadly, to any result that falls short of the talk preceding it.