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