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