Here's what rhymes with monotonic.
                        
                        
                    
                                tonic  ionic  sonic  conic  phonic  bionic  chronic  ironic  colonic  demonic  iconic  mnemonic  sardonic  laconic  subsonic  daemonic  acetonic  harmonic  tectonic  chorionic  isotonic  planktonic  platonic  catatonic  diatonic  monophonic  avionic  embryonic  ultrasonic  supersonic  diachronic  hypertonic  polyphonic  symphonic  synchronic  telephonic  electronic  hegemonic  ganglionic  histrionic  hydroponic  infrasonic  quadraphonic  quadrophonic  architectonic  stereophonic  philharmonic  pathognomonic  microelectronic  Words that almost rhyme with monotonic
atomic  comic  anatomic  autonomic  genomic  diatomic  agronomic  ergonomic  subatomic  economic  uneconomic  astronomic  tragicomic  taxonomic  gastronomic  macroeconomic  microeconomic  socioeconomic  topic  boric  logic  toxic  folic  gothic  tropic  atopic  biotic  bardic  subtopic  hayrick  rollick  cosmic  aortic  chaotic  erotic  garlic  neurotic  caustic  melodic  narcotic  carbolic  idiotic  pyloric  anabolic  anoxic  cathodic  formic  frolic  gnostic  iambic  karmic  meiotic  meteoric  myopic  nontoxic  robotic  cirrhotic  homoerotic  seraphic  strophic  chopstick  carsick  noncaloric  shambolic  placekick  historic  symbolic  metabolic  periodic  apostolic  aquatic  exotic  hydraulic  biologic  caloric  despotic  episodic  geologic  hypnotic  psychotic  systolic  isotopic  metaphoric  necrotic  phenolic  anarchic  basaltic  catabolic  dialogic  euphoric  fibrotic  hypoxic  orthodontic  thrombotic  antarctic  bucolic  diabolic  heartsick  rhapsodic  allegoric  nonnarcotic  alcoholic  patriotic  antibiotic  diastolic  isotropic  neurologic  pathologic  ascorbic  etiologic  hyperbolic  metamorphic  morphologic  parabolic  semiotic  spasmodic  symbiotic  synoptic  yardstick  agnostic  cathartic  lethargic  melancholic  pedagogic  sclerotic  demagogic  folkloric  hierarchic  unpatriotic  vitriolic  xenophobic  acrostic  ecologic  misanthropic  subarctic  workaholic  macrobiotic  sophomoric  theosophic  subtropic  aetiologic  chocoholic  gynaecologic  shopaholic  astronautic  chocaholic  horologic  diagnostic  philosophic  catastrophic  cytotoxic  histologic  macroscopic  philanthropic  prognostic  anisotropic  endoscopic  immunologic  psychologic  gynecologic  hematologic  oligarchic  polymorphic  psychotropic  quixotic  telescopic  arthroscopic  gyroscopic  nonalcoholic  posthypnotic  haematologic  seismologic  microscopic  hydrochloric  physiologic  prehistoric  pharmacologic  peristaltic  fluoroscopic  kaleidoscopic  microcosmic  meteorologic  anthropomorphic  atherosclerotic  epidemiologic  stereoscopic  bacteriologic  antispasmodic  stroboscopic  spectroscopic  submicroscopic  electroscopic