1. Evaporating readily at normal temperatures and pressures.
2. That can be readily vaporized.
3. Tending to violence; explosive, as of behavior.
1. Although mercury doesn't evaporate at normal temperatures, some would call it volatile, since it is the only metal that is liquid at room temperature.
2. Water is quite volatile, since I can vaporize it whenever I want.
3. When I got into an argument with my friend, Brian, I became quite volatile.