adjective

1. Obsolete flying or able to fly; volitant
2. vaporizing or evaporating quickly, as alcohol
3. 1. likely to shift quickly and unpredictably; unstable; explosive a volatile social condition
   2. moving capriciously from one idea, interest, etc. to another; fickle
   3. not lasting long; fleeting
4. Comput. designating or of memory that does not retain stored data when the power supply is disconnected

Etymology: MFr < L volatilis < volare, to fly

noun

1. any flying creature
2. a volatile substance