Here's what rhymes with sleepfulness.
Words that almost rhyme with sleepfulness
deceitfulness sleeplessness peacefulness gleefulness feebleness evenness deaconess treasonous dreaminess speciousness creaminess grievousness recentness ceaselessness steaminess unevenness heedlessness facetiousness speechlessness needlessness egregiousness vehemence covetousness edematous cenotaphs ingeniousness pediments