insane
UK[ɪnˈseɪn]US[ɪnˈseɪn]
adj
In a state of mind which prevents normal perception, behavior, or social interaction; seriously mentally ill.
adj
Extremely foolish; irrational.
Morpheme Breakdown
in
sane
in
not
sane
healthy mind
Etymology
The word "insane" entered English in the mid-16th century from the Latin insanus, a compound of the negative prefix in- and sanus ("healthy"). The Latin sanus itself is traced to the Proto-Indo-European root swen- ("to sound, healthy"). The literal meaning, "not healthy," was specifically applied to mental health, contrasting with the physical health connotation of its antonym "sane." Over time, its usage expanded beyond clinical contexts to describe ideas or actions perceived as utterly irrational or foolish, reflecting a metaphorical extension of being "mentally unsound."
Analysis
Structure: in (not) + sane (healthy mind)
- in: Latin origin, a prefix meaning "not".
- sane: From Latin sanus meaning "healthy, sound in mind".
Examples
The defendant was found not guilty by reason of insanity.
It would be insane to drive in this blizzard.
The chaotic scene was like something out of an insane asylum.