Here's what rhymes with runlength.
Words that almost rhyme with runlength
lens tenth sense hence dense offence thence whence fence offense tense tens cleanse gems hens pence pens dens gens glens fens hems immense stems commence theorems morphemes harems defence defense intense incense suspense condemns pretense commonsense condense recommence expense dispense recompense frankincense halfpence twopence sixpence length death health wealth breath depth breadth neath strength stealth twelfth commonwealth shibboleth