not pure or clean; not consisting of only one substance but mixed with one or more substances often of poorer quality 不纯的；不洁的；有杂质的 impure gold 不纯的金子 Some of these drugs are highly impure. 这些药物中有些是高度不纯的。
- (old-fashioned or formal)
(of thoughts or feelings 思想或感情 morally bad, especially because they are connected with sex 道德败坏的；（尤指）淫乱的 impure thoughts/motives 不纯洁的想法/动机
opposite pure
Word Originlate Middle English (in the sense ‘dirty, containing offensive matter’): from Latin impurus, from in- ‘not’ + purus ‘pure’.