Meaning

noun relatively permanent disorder of the mind

originA three-part word (root 'sane', prefix 'in-' meaning 'not', suffix '-ity', meaning 'the state of'). Derived from Latin precursory equivalents. Two possible candidates for construction order: * insane + -ity: īnsānus (“unhealthy; insane”) + -itās *: Latin īnsānus (“unsound in mind; mad, insane”), from in- + sānus (“sound, sane”). Modern forms of roots: in- + sane * in- + sanity: in- (“lacking;…

Etymology from Wiktionary, CC BY-SA 3.0