a.

1. 用之不竭的；无穷无尽的
   The people living beside the river have an inexhaustible supply of water.

   住在河边的人有取用不尽之水。

2. 不会疲劳的，不倦的
   an inexhaustible swimmer

   不知疲倦的游泳者

adj.

1. (of a supply) never ending; incapable of being used up.
2. tireless.