Words That Rhyme With "Fastness" :
2 syllables:
ansa's, cantus, chasteness, crassness, daftness, flatness, justness, moistness, pastness, patness, Santas, Shasta's, vastness, wasteness
3 syllables:
advance's, Atlanta's, augustness, discantus, distressedness, downcastness, Erastus, lightfastness, robustness, steadfastness, unjustness