Here's what rhymes with vigorous.
rigorous Words that almost rhyme with vigorous
ignorance timorous oviparous difference bitterness inference herbivorous vociferous viviparous literates dipterous wilderness coniferous illiterates inwardness omnivorous pestiferous spinnerets calciferous alliterates indifference deliverance carnivorous belligerence interments itinerants riverbanks cordilleras barbiturates belligerents insectivorous refrigerants carboniferous disfigurements nonbelligerents