"Is 'Half the beauty of a woman is her shyness' a Hadith?"

The phrase "Haya' (modesty/shyness) is the soul's shrinking from indecency" has not been found as a prophetic Hadith. Al-Hafiz Ibn Hajar defined Haya' as "the soul's shrinking from indecency," and it is a human characteristic that deters one from doing what one desires. It is a compound of timidity and chastity, hence a person possessing Haya' would not be an evildoer. Encouragement for Haya' for both men and women has been mentioned in prophetic Ahadith, among them the saying of the Messenger of Allah, peace and blessings be upon him: "Leave him, for modesty is part of faith," and "Modesty does not enter into anything but that it beautifies it."