IMPURITY. – From the Latin *impuritas*, the state of being impure, it is one of the terms used to indicate the vice against purity (q.v.). In general, it consists in the mingling with something less perfect; hence man renders himself impure when he subjects himself to creatures, loving them inordinately, which occurs in every fault. One may therefore say that impurity is the opaque element found in every action tainted by fault, but in a specific sense it is employed to denote the faults contrary to the sixth commandment, and is thus synonymous with lust (q.v.).
Legal impurity or uncleanness, in the Old Testament, is the state of one who has contracted a legal stain. It was caused by the use, contact, or proximity, according to the case, of impure things such as tombs and certain foods (Num. 19:11-22; Lev. 11), by leprosy (ibid. 13-14), and by certain phenomena relating to human generation (ibid. 12 and 15). It varied in duration and extent and deprived the contaminated person of the right to participate publicly in worship and sometimes in social life. It ceased with ritual purifications, which differed according to the species and are described in the passages cited.