Malfoy is derived from the French “mal foi”, meaning “badly faith” or “unfaithful”. In law, “bad faith” refers to a case in which a malicious motive on the part of a party in a lawsuit undermines their case. This would be relevant to the general cruel natures displayed by Lucius and Draco as well as Narcissa. In existentialism, “bad faith” is a philosophical concept in which people blame their own failures on external factors, thus denying responsibility for their actions. Also, this most likely refers to the Malfoys’ tendency to switch their loyalties to avoid danger or punishment, rather than steadfastly supporting their presented views.