a.

1. 流动的；流体的；液体的
2. 不固定的；易变的
   My holiday plans are fluid.

   我的假日计划是易变的。

3. 流畅的
   The professor praised her fluid style.

   教授称赞她流畅的文体。

n.

1. 流体，流质；液[C][U]
   All liquids and gases are fluids.

   所有液体与气体都是流体。

n.

adj.

1. able to flow easily.
2. not settled or stable.
3. smoothly elegant or graceful.
4. (of a clutch or coupling) using a liquid to transmit power.