One way to hold it: a glass that should hold one thing only, and something else has got into it. You do not always see the extra thing, but it is there, and it means what you have is no longer only what it says on the label.
可以想成一只杯子，本來裡面只該有一種東西，結果混進了別的。那個多出來的東西不一定看得見，但它在裡面。所以你手上的東西，已經不只是標籤上寫的那一樣了。每一種 impure 的用法，都可以看成這個畫面換一個場景。
From the word’s history
From Middle French impur, from Latin impūrus. The Latin word is the negative of pūrus (pure), so the word has carried the same shape of meaning — not pure — the whole way into English.
來自中古法文 impur，再往前是拉丁文 impūrus。impūrus 就是 pūrus（純的）加上否定，所以「不純」這個意思一路沒有變過。
Wiktionary entry supplied in this packet (source_ref kaikki:3f6f69a190036ae4:323977588), etymology_text: From Middle French impur, from Latin impūrus.
登入就可以看每一支怎麼連回核心畫面。