[1] Decree of the Congregation of the Holy Office in 1956, Acta Apostolicae Sedis 48, 1956, 114-145; Allocution to the World Federation of Young Women, January 18, 1952; Radio message on the Christian conscience, March 23, 1952; Allocution to the 5th International Congress of Psychotherapy and Psychology, November 13, 1953).Excerpt from Tradition in Action; http://www.traditioninaction.org
The Catholic Church always taught us that the way of dressing should meet three conditions: the needs of hygiene, modesty and decorum. Many Catholics are still aware of the first two standards, but have lost the sense of what satisfies the laws of proper decorum. The word decorum, which comes from dignity, means a way of being and manner appropriate to the dignity of your condition as a child of God, and appropriate to the respect you owe your neighbor who lives in society with you.
“These three conditions, then, serve for the proper and upright development of a man’s physical, spiritual and social nature. If you need an authoritative source to support what I am saying, there is a valuable allocution that Pius XII gave on fashion (November 8, 1957).” http://www.traditioninaction.org
++ modesty, a word that comes from modus, a measure or limit, does in fact establish certain norms and limits in clothing to protect both the moral integrity of a person and to keep her from arousing sensual desires in others. As Pope Pius XII wisely said, “Modesty is the natural bulwark of chastity … because it moderates acts closely connected with the very object of chastity.”
The natural reason for modesty you can find in a wise explanation. The parts of the body that were given to mankind by God for the preservation of the species should be reserved for the prudent discretion, intimacy and privacy of the matrimonial life. They do not have any public function and, therefore, should not be displayed in public. It is not just full nudity or a blatant show of flesh that is prohibited. Modesty also prohibits the kind of clothing that insinuates what should not be shown. This applies mainly to feminine dress.
The supernatural reason for modest behavior is obedience to the Commandments of God and to preserve the virtue of chastity either outside or inside matrimony.++
