| n. | 1. | |
| 1. | (Physics) Any substance in the gaseous, or aëriform, state, the condition of which is ordinarily that of a liquid or solid. |
| 2. | In a loose and popular sense, any visible diffused substance floating in the atmosphere and impairing its transparency, as smoke, fog, etc. |
| 3. | Wind; flatulence. |
| 4. | Something unsubstantial, fleeting, or transitory; unreal fancy; vain imagination; idle talk; boasting. |
| 5. | An old name for hypochondria, or melancholy; the blues. |
| 6. | (Pharm.) A medicinal agent designed for administration in the form of inhaled vapor. |
| v. i. | 1. | |
| 1. | To pass off in fumes, or as a moist, floating substance, whether visible or invisible, to steam; to be exhaled; to evaporate. |
| 2. | To emit vapor or fumes. |
| 3. | To talk idly; to boast or vaunt; to brag. |
| v. t. | 1. | To send off in vapor, or as if in vapor; as, to vapor away a heated fluid. |