Immaturity rhymes with:
insecurity, asperity, austerity, celebrity, charity, darity, dority, garity, garrity, gerety, gerrity, harrity, inferiority, insecurity, insularity, seniority, severity, superiority, supermajority, unpopularity, varity, vulgarity
Immaturity sounds like:
interred, intraday, intrude, intruded