n.

1. 不純；不潔[U][C]
2. 不道德；淫猥；瀆神[U][C]
3. 雜質；不純之物；不潔之物[C]
   Filtering the water removed some of its impurities.

   把水過濾一下除去了一些雜質。

n.

1. the quality or condition of being impure.
2. a constituent which impairs the purity of something.
3. Electronics  a trace element deliberately added to a semiconductor; a dopant.