Here's what rhymes with obseratum.
erratum Words that almost rhyme with obseratum
button mutton piton sudden exciton glutton dudgeon scutcheon nubbin dubbin globin bludgeon escutcheon unbutton androgen bellybutton custom caecum secundum accustom cementum jejunum buxom buncombe bunkum dumdum humdrum corundum colostrum conundrum carborundum