Insanity rhymes with:
sanity, inhumanity, profanity, sanity, vanity, affinity, alkalinity, amenity, community, conaty, dignity, disunity, divinity, eternity, femininity, fraternity, gaynatie, immunity, indemnity, indignity, infinity, inhumanity, masculinity, mcginnity, modernity, opportunity, profanity, salinity, sanity, serenity, solemnity, trinity, unity, vanity, vicinity
Insanity sounds like:
imagined, incant, incessant, incognito, ingenito, ingenuity, innocent, innocenti, inseminate, insinuate, insinuated, insouciant