C.S. Lewis on modesty and societal propriety
“The Christian rule of chastity must not be confused with the social rule of “modesty” (in one sense of that word: i.e. propriety, or decency). The social rule of propriety lays down how much of the human body should be displayed and what subjects can be referred to, and in what words, according to the customs of a given social circle.
Thus, while the rule of chastity is the same for all Christians at all times, the rule of propriety changes. A girl in the Pacific islands wearing hardly any clothes and a Victorian lady completely covered in clothes might both be equally “modest,” proper, and decent, according to the standards of their own societies; and both, for all we can tell by their dress, might be equally chaste (or equally unchaste).”
— Mere Christianity