volatile
/ˈvɒl.ə.taɪl/adjective
likely to change suddenly and unpredictably; (of a liquid) turning easily into gas
нестабильный, переменчивый; летучий
Существительное: volatility. Часто: a volatile market, situation, temper.
“Oil prices have been volatile this year.”
“The situation in the region is volatile.”
“He has a volatile temper and shouts easily.”