Pronunciation: (vā'pur),[key] —n. 1. a visible exhalation, as fog, mist, steam, smoke, or noxious gas, diffused through or suspended in the air: the vapors rising from the bogs. 2. Physics.a gas at a temperature below its critical temperature.
3. a substance converted into vapor for technical or medicinal uses.
4. a combination of a vaporized substance and air.
5. gaseous particles of drugs that can be inhaled as a therapeutic agent.
6. Archaic. a. a strange, senseless, or fantastic notion.
b. something insubstantial or transitory.
7. vapors,Archaic. a. mental depression or hypochondria.
b. injurious exhalations formerly supposed to be produced within the body, esp. in the stomach.
—v.t. 1. to cause to rise or pass off in, or as if in, vapor; vaporize.
2. Archaic.to affect with vapors; depress.
—v.i. 1. to rise or pass off in the form of vapor.
2. to emit vapor or exhalations.
3. to talk or act grandiloquently, pompously, or boastfully; bluster. Also,esp. Brit.,vapour.