Here's what rhymes with opeiation.
                        
                        
                    
                                operation  nation  aberration  adoration  aeration  relation  creation  duration  radiation  station  admiration  deviation  agitation  alteration  aspiration  saturation  aviation  maturation  mediation  moderation  appellation  automation  donation  iteration  oration  ablation  adulation  dilation  elation  education  situation  application  formation  generation  cooperation  corporation  location  observation  separation  variation  activation  adaptation  liberation  obligation  rotation  taxation  allocation  decoration  notation  temptation  vacation  vibration  affirmation  animation  approbation  causation  cessation  elaboration  evaporation  federation  graduation  habitation  irradiation  modulation  narration  negation  ordination  oscillation  probation  toleration  vocation  allegation  alternation  citation  damnation  gestation  hydration  perforation  perspiration  perturbation  reparation  sedation  summation  ulceration  abdication  annotation  population  combination  association  foundation  imagination  occupation  preparation  publication  appreciation  correlation  cultivation  declaration  elevation  indication  inflation  innovation  inspiration  isolation  migration  motivation  orientation  realization  restoration  salvation  sensation  violation  alienation  arbitration  collaboration  deformation  delegation  dissertation  domination  estimation  fixation  imitation  initiation  irrigation  irritation  medication  meditation  navigation  nomination  oxidation  plantation  propagation  quotation  recreation  respiration  termination  vegetation  accusation  affiliation  aggregation  annexation  authorization  calibration  compilation  dedication  derivation  desolation  desperation  dilatation  dissipation  dissociation  exaggeration  expiration  fabrication  fascination  filtration  litigation  mutation  realisation  retaliation  starvation  validation  veneration  abbreviation  affectation  amputation 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condensation  consolation  deliberation  deprivation  dislocation  distillation  emigration  fermentation  importation  incarnation  insulation  ionization  modernization  optimization  polarization  ratification  reformation  replication  retardation  adjudication  augmentation  authentication  cancellation  commendation  conformation  constellation  consternation  constipation  consummation  culmination  denunciation  deputation  devastation  emulation  enumeration  escalation  exaltation  exhortation  fertilization  fibrillation  gravitation  imputation  inactivation  inauguration  invocation  ovulation  provocation  recitation  regurgitation  renovation  renunciation  repudiation  revocation  usurpation  vindication  visitation  organization  concentration  consideration  examination  explanation  interpretation  determination  participation  presentation  regulation  calculation  differentiation  expectation  exploitation  formulation  justification  organisation  stimulation  transportation  anticipation  assimilation  congregation  consultation  contemplation  elimination  emancipation  illumination  inclination  inflammation  proclamation  proliferation  registration  resignation  segregation  simulation  speculation  utilization  amplification  articulation  coagulation  colonization  denomination  dissemination  evacuation  excavation  gratification  humiliation  incubation  infiltration  mobilization  notification  preoccupation  pronunciation  subordination  amalgamation  capitulation  categorization  conciliation  confederation  confiscation  consecration  deregulation  devaluation  dispensation  duplication  elucidation  exportation  implantation  inoculation  interrogation  intimidation  liquidation  magnetization  menstruation  mortification  prolongation  reclamation  refrigeration  refutation  resuscitation  stipulation  utilisation  vaccination  civilization  classification  investigation  transformation  demonstration  approximation  confrontation  consolidation  contamination  continuation  manifestation  manipulation  precipitation  qualification  specification  civilisation  fragmentation  generalization  globalization  intoxication  localization  multiplication  privatization  purification  remuneration  socialization  sophistication  specialization  stabilization  stratification  unification  verification  calcification  capitalization  conflagration  exclamation  extermination  hybridization  immunization  magnification  normalization  ornamentation  polymerization  quantification  sedimentation  segmentation  sterilization  supplementation  administration  communication  identification  representation  accumulation  configuration  discrimination  implementation  characterization  documentation  recommendation  reconciliation  rehabilitation  clarification  disintegration  liberalization  reorganization  signification  transplantation  argumentation  centralization  crystallization  democratization  diversification  hospitalization  nationalization  personification  rationalization  simplification  standardization  visualization  industrialization  instrumentation  intensification  synchronization  experimentation  decentralization  conceptualization  excommunication  misrepresentation  Words that almost rhyme with opeiation
haven  basin  hasten  occasion  evasion  equation  invasion  persuasion  taken  pagan  shaken  bacon  laden  maiden  layman  laymen  shaman  patron  awaken  straighten  undertaken  salesman  forsaken  tradesmen  mistaken  statesman  contagion  overtaken