volatility
noun /ˌvɒləˈtɪləti/
  /ˌvɑːləˈtɪləti/
[uncountable]- (often disapproving) the quality in a person of changing easily from one mood to another
- There was concern about the father's volatility.
 
 - the quality in a situation of being likely to change suddenly synonym instability (1)
- The economy is set to recover, despite recent stock market volatility.
 
 - (specialist) the quality in a substance of changing easily into a gas
- The cold reduces the volatility of the substance.