Here's what rhymes with external.
                        
                        
                    
                                journal  sternal  eternal  colonel  kernel  diurnal  vernal  internal  maternal  paternal  fraternal  infernal  nocturnal  Words that almost rhyme with external
dermal  thermal  epidermal  isothermal  geothermal  hydrothermal  purple  turtle  chervil  burble  burgle  circle  verbal  fertile  girdle  servile  hurdle  myrtle  gurgle  curdle  hurtle  commercial  dispersal  squirrel  tubercle  hurtful  inertial  infertile  deferral  encircle  illiberal  scleral  subdural  clitoral  mirthful  forkful  demurral  disbursal  reversal  referral  rehearsal  epidural  puerperal  conferral  infomercial  nonverbal  semicircle  bicameral  universal  controversial  transversal  noncommercial  transferal  noncontroversial