1. Not pure; not clean; dirty; foul; filthy; containing something which is unclean or unwholesome; mixed or impregnated extraneous substances; adulterated; as, impure water or air; impure drugs, food, etc.
2. Defiled by sin or guilt; unholy; unhallowed; said of persons or things.
3. Unchaste; lewd; unclean; obscene; as, impure language or ideas. Impure desires.
4. Not purified according to the ceremonial law of Moses; unclean.
5. Not accurate; not idiomatic; as, impure Latin; an impure style.
Origin: L. Impurus; pref. Im- not – purus pure: cf. F. Impur. See pure.