1ADJ-GRADED 不纯的;不洁的;掺杂的 A substance that is impure is not of good quality because it has other substances mixed with it. 不纯的;不洁的;掺杂的
2ADJ-GRADED 淫乱的;不贞洁的 If you describe thoughts and actions as impure, you mean they are concerned with sex and are morally bad. 淫乱的;不贞洁的 [old-fashioned]