Here's what rhymes with grumpus.
                        
                        
                    
                                compass  encompass  Words that almost rhyme with grumpus
bunches  sponges  lameness  roughness  trumpets  numbness  rashness  luckless  pumice  alumnus  loveless  tapas  duchess  fulness  sumptuous  toughness  baseness  bloodless  buttress  dullness  dulness  lustrous  piteous  puppets  cumbrous  talus  cutlass  hummocks  unctuous  justice  buckets  buttocks  colourless  fungus  muskets  oneness  wondrous  cements  couplets  stasis  stomachs  bulbous  doublets  justness  nuggets  bluntness  smugness  substance  judgments  judgements  neuritis  repugnance  robustness  abruptness  druggists  incubus  numinous  pedants  abundance  reluctance  circumference  abutments  encumbrance  hundredths  unrighteousness  wantonness  effulgence  fistulous  incumbrance  adjustments  indulgence  conductance  inductance  incumbents  remonstrance  resultants  consultants  reasonableness  readjustments  unreasonableness  superabundance