/ ˈvɒlətaɪl; NAmE ˈvɑːlətl/ adjective
1.
(often disapproving ) ( of a person or their moods ) changing easily from one mood to another :
a highly volatile personality
2.
( of a situation ) likely to change suddenly; easily becoming dangerous
SYN unstable :
a highly volatile situation from which riots might develop
a volatile exchange rate
3.
( technical ) ( of a substance ) that changes easily into a gas :
Petrol is a volatile substance.
► vola·til·ity / ˌvɒləˈtɪləti; NAmE ˌvɑːl-/ noun [ U ]
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WORD ORIGIN
Middle English (in the sense creature that flies , also, as a collective, birds ): from Old French volatil or Latin volatilis , from volare to fly.