vol·a·tile 
(vŏlə-tl, -tīl′)
(vŏlə-tl, -tīl′)adj.
1. Chemistry
a. Evaporating readily at normal temperatures and pressures.
b. Capable of being readily vaporized.
2.
a. Tending to vary often or widely, as in price: the ups and downs of volatile stocks.
b. Inconstant; fickle: a flirt's volatile affections.
c. Lighthearted; flighty: in a volatile mood.
d. Ephemeral; fleeting.
3. Tending to violence; explosive: a volatile situation with troops and rioters eager for a confrontation.
4. Flying or capable of flying; volant.
5. Computers Of or relating to memory whose data is erased when the memory's power is interrupted.
[French, from Old French, from Latin volātilis, flying, from volātus, past participle of volāre, to fly.]
vola·tile n.
vol′a·tili·ty (-tĭlĭ-tē), vola·tile·ness (-tl-nĭs, -tīl′-) n.