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