Quidam
Defined in 2 dictionaries — Black's (1910), Bouvier (1839)
Black's Law Dictionary
Henry Campbell Black, M.A. · 1910
Lat Somebody. This term is used in the French law to designate a person whose name is not known.
A Law Dictionary, Adapted to the Constitution and Laws of the United States
John Bouvier · 1839
some one; somebody. French law. This latin word is used dam is usually described by the features of his face,’ the colour of his hair, his height, his clothing, and the like, in any process which may be issued against him. Merl. Répert. h. t.; Encyclopédie, h. t. aa