Black's Law Dictionary (2nd edition)dictionaries

Pia Fraus

Lat A pious fraud; a subterfuge or evasion considered morally justifiable on account of the ends sought to be promoted. Partlcularly applied to an evasion or disregard of the laws in the Interests of religion or religious institutions, such as circumventing the statutes of mortmain

Source: Black's Law Dictionary 2nd Ed (1910)