Cracker

1. One who, or that which, cracks.
2. A noisy boaster; a swaggering fellow.
3. A small firework, consisting of a little powder inclosed in a thick paper cylinder with a fuse, and exploding with a sharp noise; -- usually called firecracker.
4. A thin, dry biscuit, often hard or crisp; as, a Boston cracker; a Graham cracker; a soda cracker; an oyster cracker.
5. A nickname to designate a poor white in some parts of the Southern United States.
6. (Zoöl.) The pintail duck.