volatile

(noun) a volatile substance; a substance that changes readily from solid or liquid to a vapor. Example: "It was heated to evaporate the volatiles."

(adj) evaporating readily at normal temperatures and pressures. Synonyms: volatile (vs. nonvolatile). Examples: "Volatile oils." "Volatile solvents."

(adj) liable to lead to sudden change or violence. Synonyms: explosive. Examples: "An explosive issue." "A volatile situation with troops and rioters eager for a confrontation."

(adj) marked by erratic changeableness in affections or attachments. Synonyms: fickle. Examples: "Fickle friends." "A flirt's volatile affections."

(adj) tending to vary often or widely. Examples: "Volatile stocks." "Volatile emotions."