Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
insānĭtas, ātis, f. [insanus], unsoundness, unhealthiness, disease: nomen insaniae significat mentis aegrotationem et morbum, id est insanitatem et aegrotum animum, Cic. Tusc. 3, 4, 8: sapientia sanitas sit animi, insipientia autem quasi insanitas quaedam, id. ib. 3, 5, 10; cf. Varr. ap. Non. 122, 28.