Define volatile: likely to change in a very sudden or extreme way — volatile in a sentence. Get Word of the Day daily email, delivered to your inbox!. This man looks like a very volatile person. Licensed from iStockPhoto. adjective. The definition of volatile is tending to become violent or something that is rapidly. Define volatile (adjective) and get synonyms. What is volatile (adjective)? volatile (adjective) meaning, pronunciation and more by Macmillan Dictionary. The Girl from Sunset Ranch Amy Bell Marlowe. More submissions sologamy long tom deforest deep-plan MOMA logogriph gilded cage urban furniture Judas kiss view entries. Figi Jul 16, casino 777 fortuna ixtapaluca When left unused, make-up has a tendency to dry out because any water or other volatile substances it contains evaporate. Definition and synonyms of volatile from the online English dictionary from Macmillan Publishers Limited. Blog A must for anyone with an interest in the changing face of language.