impure has 1 distinct synonym spread across 1 of its 3 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is pure.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
combined with extraneous elements
(used of persons or behaviors) immoral or obscene
“impure thoughts”
having a physical or moral blemish so as to make impure according to dietary or ceremonial laws
“unclean meat”
Synonyms, antonyms and the broader and narrower relations for impure come from Princeton University’s WordNet. Full sources and licences.