plea of insanity pleadingness • pleaproof · · · Info · Definitions · Synonyms · Characters · · plea of insanity · · Text Common · · Latin · · Scripts 16 · · Length 6 · · Syllables Definitions · · · (noun) (criminal law) a plea in which the defendant claims innocence due to mental incompetence at the time. Synonyms: insanity plea, plea of insanity. · · Noun Definition 1 Synonyms · · · insanity plea · · Synonym 1 Characters · · space U+0020 a latin small letter a U+0061 e latin small letter e U+0065 f latin small letter f U+0066 i latin small letter i U+0069 l latin small letter l U+006C n latin small letter n U+006E o latin small letter o U+006F p latin small letter p U+0070 s latin small letter s U+0073 t latin small letter t U+0074 y latin small letter y U+0079