Meaning
"unclean, impure" (a, negative, kathairo, "to purify"), is used (a) of "unclean" spirits, frequently in the Synoptists, not in John's gospel; in Act 5:16, Act 8:7, Rev 16:13, Rev 18:2 (in the 2nd clause the birds are apparently figurative of destructive satanic agencies); (b) ceremonially, Act 10:14, Act 10:28, Act 11:8, 1Co 7:14; (c) morally, 2Co 6:17, including (b), RV; "no unclean thing;" Eph 5:5, Rev 17:4, RV, "the unclean things" (AV follows the text which have the noun akathartes, "the filthiness").
"common," is translated "unclean" in Rom 14:14 (thrice); in Rev 21:27, RV (AV, "that defileth," follows the inferior texts which have the verb koinoo: see B). See COMMON, DEFILE, C, UNHOLY, No. 2.
to make koinos, "to defile," is translated "unclean" in Heb 9:13, AV, where the perfect participle, Passive, is used with the article, hence the RV, "them that have been defiled." See DEFILE, A, No. 1.
akin to A, No. 1, denotes "uncleanness," (a) physical, Mat 23:27 (instances in the papyri speak of tenants keeping houses in good condition); (b) moral, Rom 1:24, Rom 6:19, 2Co 12:21, Gal 5:19, Eph 4:19, Eph 5:3, Col 3:5, 1Th 2:3 (suggestive of the fact that sensuality and evil doctrine are frequently associated); 1Th 4:7.
Note: In 2Pe 2:10, AV, miasmos, "a defilement," is rendered "uncleanness;" see DEFILEMENT, B, No. 2.