Caput lupinum or caput gerat lupinum is a term used in the English legal system and its derivatives.[1] The term literally means "wolf's head" or "wolfish head" and refers to a person considered to be an outlaw, as in, e.g., the phrase caput gerat lupinum ("may he wear a wolfish head" / "may his be a wolf's head"). Black's Law Dictionary, 8th edition (2004: 225) reads "an outlawed felon considered a pariah - a lone wolf - open to attack by anyone." A person designated a caput lupinum was a criminal whose rights had been waived. As such, s/he could be legally harmed by any citizen.
The Yale University secret society Wolf's Head is named after this phrase in reference to the idea that the society is a separate world to whose members (at least when interacting with each other in their capacity as such) neither the outside world's prohibitions nor its protections apply.