Here's what rhymes with forgetfulness.
                        
                        
                    
                                fretfulness  Words that almost rhyme with forgetfulness
dreadfulness  carefulness  restfulness  zestfulness  carelessness  gentleness  tetanus  garrulous  helpfulness  healthfulness  eventfulness  levelness  resentfulness  fetidness  perilous  restlessness  credulous  recklessness  pendulous  querulous  sedulous  fecklessness  respectfulness  terribleness  testiness  mechanise  neglectfulness  tepidness  heftiness  resonance  genesis  helplessness  mellitus  membranous  pestilence  sensuous  tenuous  blessedness  licentiousness  nebulous  tremulous  venomous  breathlessness  clarinets  petulance  baronets  preciousness  senselessness  relentlessness  portentousness  redolence  sensibleness  djellabas  marabous  jellabas  dextrousness  settlements  negligence  prevalence  relevance  feminists  stenosis  decadence  precipice  hydrocephalus  incredulous  preeminence  preparedness  requisites  conscientiousness  pleasantness  emeritus  overemphasis  detriments  megabits  momentousness  decimates  sentiments  regiments  specialists  benevolence  precedence  sediments  tenements  asparagus  beneficence  irrelevance  malevolence  testaments  celebrants  pretentiousness  contentiousness  decadents  directionless  infectiousness  defencelessness  defenselessness  impetuousness  contemptuousness  nonvenomous  tempestuousness  incestuousness  intelligence  inheritance  precedents  prerequisites  temperaments  unpleasantness  geneticists  morphogenesis  registrants  interrogates  unpreparedness  tendentiousness  secondments  housemistress  experiments  impediments  pathogenesis  integuments  nonresidents  presentiments  nonspecialists  perfectionists  developments  embarrassments  angiogenesis  embryogenesis  disinheritance  gluconeogenesis  spermatogenesis  redevelopments