Here's what rhymes with semiarbitrary.
                        
                        
                    
                                arbitrary  prairie  very  vary  marry  fairy  merry  bury  dairy  ferry  wary  cherry  hairy  berry  papillary  sherry  tarry  parry  harry  nary  tare  apiary  barre  terry  faerie  wherry  ordinary  budgetary  scary  ternary  remarry  unwary  bacillary  pessary  bilberry  topiary  plagiary  literary  temporary  capillary  dietary  urinary  legendary  pituitary  ancillary  corollary  estuary  honorary  obituary  statuary  canary  tutelary  aviary  beriberi  breviary  buffoonery  legionary  actuary  equerry  humeri  lapidary  elderberry  nondairy  military  customary  pulmonary  coronary  hereditary  solitary  adversary  disciplinary  judiciary  maxillary  proprietary  tributary  unitary  dysentery  planetary  salutary  sedentary  veterinary  apothecary  emissary  fiduciary  funerary  itinerary  mortuary  epistolary  luminary  dromedary  huckleberry  chokecherry  sectary  necessary  secondary  secretary  missionary  monetary  commentary  dictionary  imaginary  monastery  sanctuary  stationary  subsidiary  cemetery  involuntary  momentary  pecuniary  sanitary  visionary  mercenary  seminary  commissary  culinary  sanguinary  savagery  stationery  cautionary  centenary  dignitary  cassowary  voluptuary  nonliterary  tercentenary  uncustomary  contemporary  preliminary  unnecessary  vocabulary  beneficiary  fragmentary  reactionary  functionary  deflationary  genitourinary  interplanetary  paramilitary  probationary  supernumerary  unsanitary  diversionary  insanitary  nonmilitary  undersecretary  recessionary  bicentenary  extraordinary  revolutionary  evolutionary  discretionary  inflationary  interdisciplinary  cardiopulmonary  multidisciplinary  expeditionary  constabulary  concessionary  eleemosynary  geostationary  elocutionary  nonhereditary  exclusionary  confectionery  expansionary  counterrevolutionary  Words that almost rhyme with semiarbitrary
belly  allele  jelly  deli  telly  smelly  underbelly  vermicelli  ready  rarely  levy  levee  breathy  dressy  leggy  recce  many  heavy  fairly  barely  plenty  semi  lengthy  petty  penny  fleshy  heady  messy  jetty  teddy  bevy  trendy  aplenty  faery  jenny  libretti  thready  kepi  lefty  sedgy  veggie  already  twenty  healthy  steady  wealthy  deadly  freshly  gentry  frenzy  antennae  apoplexy  carefree  medley  sentry  sexy  sketchy  sweaty  unfairly  vestry  belfry  deathly  fleshly  gayety  hefty  pebbly  tempi  testy  pesky  preciously  wetly  directly  especially  friendly  scarcely  gently  epilepsy  unhealthy  densely  squarely  deftly  spaghetti  unsteady  coquetry  machete  stealthy  sullenly  confetti  fidgety  tensely  marquetry  adeptly  effendi  assembly  correctly  elementary  expressly  immensely  unfriendly  excellency  halfpenny  complexly  hostelry  narcolepsy  sacredly  baronetcy  catalepsy  deviancy  maidenly  ineptly  woodenly  indirectly  intensely  intently  grotesquely  reassembly  complementary  incorrectly  confusedly  ambivalently  penitently  cognoscenti  equivalently  circumspectly