a.

1. 用之不竭的；無窮無盡的
   The people living beside the river have an inexhaustible supply of water.

   住在河邊的人有取用不盡之水。

2. 不會疲勞的，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.