1. (n.) Any substance in the gaseous, or aeriform, state, the condition of which is ordinarily that of a liquid or solid.

2. (n.) In a loose and popular sense, any visible diffused substance floating in the atmosphere and impairing its transparency, as smoke, fog, etc.

3. (n.) Wind; flatulence.

4. (n.) Something unsubstantial, fleeting, or transitory; unreal fancy; vain imagination; idle talk; boasting.

5. (n.) An old name for hypochondria, or melancholy; the blues.

6. (n.) A medicinal agent designed for administration in the form of inhaled vapor.

7. (n.) To pass off in fumes, or as a moist, floating substance, whether visible or invisible, to steam; to be exhaled; to evaporate.

8. (n.) To emit vapor or fumes.

9. (n.) To talk idly; to boast or vaunt; to brag.

10. (v. t.) To send off in vapor, or as if in vapor; as, to vapor away a heated fluid.