Here's what rhymes with authoritatively.
                        
                        
                    
                                qualitatively  imitatively  creatively  meditatively  appreciatively  collaboratively  legislatively  manipulatively  administratively  Words that almost rhyme with authoritatively
basically  irritatingly  abrasively  amazingly  evasively  hesitatingly  pervasively  accommodatingly  gratingly  piratically  jadedly  persuasively  unfailingly  animatedly  scathingly  fascinatingly  aggravatingly  lackadaisically  ragingly  unhesitatingly  algebraically  deprecatingly  devastatingly  prosaically  entertainingly  penetratingly  unavailingly  illuminatingly  complicatedly  nauseatingly  titillatingly  engagingly  exaggeratedly  calculatingly  infuriatingly  invigoratingly  excruciatingly  uncomplainingly  exasperatingly  humiliatingly  ingratiatingly  exasperatedly  intimidatingly