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