Here's what rhymes with heptasyllable.
rubble double trouble bubble publ playable flyable stubble friable redouble filtrable vocable unplayable dividable addable imperishable damnable indissoluble dirigible attachable unlikable acquirable vincible beatable tamable conformable imperturbable uncharitable unbridgeable nonviable unnameable ignitable unloveable exploitable translatable indemonstrable unarguable containable transmutable compoundable untranslatable Words that almost rhyme with heptasyllable
rappel couple subtle shuttle muddle puddle suppl supple huddle tuple cuddle cudgel fuddle rebuttal scuttle befuddle decouple uncouple oversubtle thermocouple rumble rustle ruffle runnel struggle muscle humble tunnel puzzle bustle funnel muzzle shovel tumble buckle chuckle crumble jumble shuffle tional grumble hovel hustle knuckle muffle mussel subtile fumble juggle mumble phrasal suckle tussle bumble caecal truffle guzzle nuzzle pummel truckle duckbill gunnel lungful rumple tamale tousle gumball tubful bundle frontal jungle fungal crustal ductile stumble ductal lustful scuffle smuggle pustule crumple reshuffle snaffle snuggle trundle bungle snuffle jugful tumbrel mugful pinocle triumphal autumnal colourful nuptial bestowal trustful duodecimal unbuckle heptagonal kerfuffle cupsful disgruntle prefrontal conformal distrustful honeysuckle peduncle carbuncle prenuptial nonvocal subcortical suboptimal mistrustful granduncle antifungal