a.

1. （液体等）易挥发的
   Gasoline is volatile.

   汽油是易挥发的。

2. 易发作的；爆炸性的
   The situation in that area was tense, dangerous and volatile.

   该地区的局势紧张、危险，且有一触即发之势。

3. 易变的；反复无常的；轻浮的
4. 活泼的；轻快的
5. 飞逝的；短暂的

adj.

1. (of a substance) easily evaporated at normal temperatures.
2. liable to change rapidly and unpredictably, especially for the worse.
   ▸liable to display rapid changes of emotion.
3. (of a computer's memory) retaining data only as long as there is a power supply connected.

n.