E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
A game at cards: so called because the players brag of their cards to induce the company to make bets. The principal sport of the game is occasioned by any player bragging that he holds a better hand than the rest of the party, which is declared by saying I brag, and staking a sum of money on the issue. (Hoyle.)
Brag is a good dog, but Holdfast is a better. Talking is all very well, but doing is far better.
Jack Brag. A vulgar, pretentious braggart, who gets into aristocratic society, where his vulgarity stands out in strong relief. The character is in Theodore Hooks novel of the same name.
He was a sort of literary Jack Brag.T. H. Burton.