μιαίνω meant originally to stain, as with color. μολύνω meant originally to smear over, as with mud or filth, always having a bad meaning, while the meaning of μιαίνω might be either good or bad. According to classical Greek, μιαίνω has a religious meaning, to profane, while μολύνω is simply to spoil, disgrace. As ethically applied in the N.T. they have both practically the same meaning, to pollute, defile. It is, however, true that μιαίνω, to judge from classical usage, refers chiefly to the effect of the act not on the individual, but on others, on the community.