Here's what rhymes with postcombustion.
                        
                        
                    
                                combustion  Words that almost rhyme with postcombustion
custom  accustom  button  dozen  conduction  compulsion  luncheon  dudgeon  toughen  unbutton  bunion  piton  dustman  dubbin  someone  sudden  conjunction  cousin  induction  junction  drunken  suction  summon  abduction  dungeon  mutton  sullen  sunken  tungsten  androgen  concussion  convulsion  compunction  fuckin  irruption  yeomen  bludgeon  gunman  impulsion  muffin  coven  dustpan  mullion  roughen  scutcheon  caparison  nubbin  kuchen  function  production  construction  consumption  reduction  corruption  deduction  eruption  injunction  interruption  emulsion  percussion  repulsion  seduction  sultan  muslin  perdition  propulsion  shrunken  transduction  avulsion  globin  huntsman  subduction  escutcheon  glutton  gulden  gumption  lumpen  scullion  decagon  stuntman  grunion  biathlon  discussion  assumption  instruction  obstruction  disruption  expulsion  deconstruction  revulsion  exciton  overproduction  ragamuffin  bellybutton  destruction  introduction  reconstruction  reproduction  dysfunction  presumption  resumption  disjunction  malfunction  semicolon  repercussion  liposuction  misconstruction  underproduction  reintroduction