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