$ 0 0 sane /sān/ Adjective (of a person) Of sound mind; not mad or mentally ill: “hard work kept me sane”. (of an undertaking or manner) Reasonable; sensible. in·sane /inˈsān/ Adjective In a state of mind that prevents normal perception, behavior, or social interaction; seriously mentally ill. (of an action or quality) Characterized or caused by madness. Got it?