Here's what rhymes with gruesomest.
                        
                        
                    
                                Words that almost rhyme with gruesomest
loosest  crudest  rudest  cruelest  lewdest  unit  newest  fewest  coolest  soonest  bluest  oculist  shrewdest  duellist  hugest  nudest  prudent  mutant  fluent  tumult  coolant  cartoonist  truant  rootlet  canoeist  obtusest  movement  student  pollutant  diluent  souvent  smoothest  annuitant  bassoonist  sunhat  amusement  pursuant  recruitment  inducement  adjuvant  imprudent  impudent  confluent  mouvement  intuit  insouciant  improvement  translucent  disputant  entombment  quadruplet  profusest