Here's what rhymes with synergeneic.
                        
                        
                    
                                antigenic  splenic  eugenic  neurogenic  phrenic  pyogenic  allergenic  photogenic  irenic  telegenic  pathogenic  schizophrenic  biogenic  cryogenic  mutagenic  psychogenic  teratogenic  androgenic  hypoallergenic  transgenic  iatrogenic  neurasthenic  carcinogenic  anthropogenic  hallucinogenic  calisthenic  callisthenic  Words that almost rhyme with synergeneic
epidemic  pfennig  academic  systemic  endemic  polemic  pandemic  totemic  epistemic  ischemic  leukaemic  nonacademic  energetic  technic  benthic  derrick  poetic  authentic  acetic  majestic  pelvic  angelic  ascetic  esoteric  ferric  relic  enteric  peptic  allelic  eutectic  steric  medic  fetich  pectic  magnetic  genetic  sympathetic  generic  kinetic  synthetic  athletic  diabetic  metric  pathetic  forensic  numeric  phonetic  septic  aseptic  centric  cleric  hectic  emetic  empathetic  psychedelic  sceptic  turmeric  dietetic  geodesic  geodetic  hermetic  hysteric  inauthentic  acerbic  homiletic  bathetic  domestic  aesthetic  prophetic  anesthetic  symmetric  cosmetic  epileptic  esthetic  mesenteric  alphabetic  anaesthetic  apathetic  diuretic  obstetric  cybernetic  frenetic  isomeric  kinesthetic  monomeric  skeptic  tartaric  anorexic  chimeric  antithetic  evangelic  lovesick  paramedic  paraplegic  gametic  paregoric  redbrick  unaesthetic  unauthentic  exegetic  electric  arithmetic  atmospheric  dialectic  dielectric  eccentric  geometric  antiseptic  apologetic  asymmetric  concentric  eclectic  parametric  econometric  isometric  prosthetic  unsympathetic  ethnocentric  ferromagnetic  photometric  apoplectic  dyslexic  dyspeptic  geocentric  ionospheric  peripatetic  anorectic  polytechnic  pyrotechnic  splenetic  thermometric  diametric  parenthetic  nonathletic  unesthetic  copacetic  phrenetic  dyslectic  phylogenetic  psychometric  barometric  biosynthetic  egocentric  geomagnetic  neuroleptic  ontogenetic  alphanumeric  heliocentric  antipathetic  cataleptic  nonmagnetic  unapologetic  narcoleptic  telekinetic  nonelectric  psychokinetic  volumetric  parasympathetic  photosynthetic  antidiuretic  nonparametric  paramagnetic  anthropocentric  radiometric  onomatopoetic  cliometric  photoelectric  colorimetric  isoelectric  pharmacokinetic  stoichiometric  trigonometric  electromagnetic  hydroelectric  piezoelectric