Here's what rhymes with fourthfifth.
fifth Words that almost rhyme with fourthfifth
sieves scythes riffs skiffs sniffs whiffs stiffs gives lives myths cliffs smiths writhes clefs withes forgives mastiffs relives goldsmiths hieroglyphs silversmiths blacksmiths monoliths filth scythe myth sixth width forthwith pith smith writhed writhe plinth hyacinth labyrinth therewith herewith silversmith wherewith monolith