a.

1. （情绪）易变的；反复无常的
   He has a mercurial disposition that changes with the situation he is in.

   他脾气反复无常，随情况而异。

2. 敏捷的；精明的
3. 水银的；汞的
4. （常作M-）【罗神】莫丘里神的；【天】水星的

n.

1. 【药】汞制剂

adj.

1. subject to sudden changes of mood or mind.
2. of or containing the element mercury.
3. (Mercurial) of the planet Mercury.

n.