Here's what rhymes with posthuma.
puma summa satsuma Words that almost rhyme with posthuma
tuna duenna lacuna vicuna stupa tua tuba chukka doodah ua hua pupa hula scuba pukka supra fistula sutra helluva bazooka beluga louvre appaloosa manoeuvre macula scrofula barracuda hallelujah outmanoeuvre incunabula