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