from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
FURIOSUS. An insane man; a madman; a lunatic.
2. In general, such a man can make no contract, because he has no
capacity or will: Furiosus nullum negotium genere potest, quia non
intelligit quod agit. Inst. 3, 20, 8. Indeed, he is considered so incapable
of exercising a will, that the law treats him as if he were absent: Furiosi
nulla voluntas est. Furiosus absentia loco est. Dig. lib. 1, tit. ult. 1.
40, 1. 124, Sec. 1. See Insane; Non compos mentis.