Here's what rhymes with howness.
brownness Words that almost rhyme with howness
aureus ous foulness countess soundness loudness bounteous soundless stoutness outface owlets doubtless countless boundless prowess roundness devoutness roundups allowance cloudless groundless thousandths unsoundness viscountess accountants groundnuts leprous mountebanks profoundness announcements endowments denouncements pronouncements