Insecurity rhymes with:
immaturity, asperity, austerity, celebrity, charity, darity, dority, garity, garrity, gerety, gerrity, harrity, immaturity, inferiority, insularity, seniority, severity, superiority, supermajority, unpopularity, varity, vulgarity
Insecurity sounds like:
immigrate, immigrated, inaccurate, inaugurate, inaugurated, incurred, ingratiate, ingrid, injured, inquired, insert, inserted, insured