IMPURITY. - From the Lat. impuritas, the state of being impure, it is one of the terms used to indicate the vice against purity (v.). In general, it consists in mixture with something less perfect: thus man becomes impure when he subjects himself to creatures, loving them in a disordered manner, which occurs in every sin. It may therefore be said that i. is the opaque element found in every action contaminated by sin, but in its specific sense it is used to denote sins contrary to the sixth commandment, lust (v.).
Legal i., or uncleanness, in the Old Testament, is the state of one who has incurred legal defilement. It was caused by the use, contact, or proximity, according to the cases, of impure things such as tombs and certain foods (Num. 19, 11-22; Lev. 11), by leprosy (ibid. 13-14), and by certain phenomena related to human generation (ibid. 12 and 15). It varied in duration and extent and deprived the contaminated person of the right publicly to participate in worship and sometimes in social life. It ceased through ritual purifications, varying according to the kinds and described in the passages cited.