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