Here's what rhymes with proprietarily.
                        
                        
                    
                                monetarily  Words that almost rhyme with proprietarily
perfidy  churlishly  stirringly  turgidly  vertically  adversity  maternity  paternity  furtively  reassuringly  searchingly  assertively  girlishly  unnervingly  cursively  subversively  discerningly  imperfectly  infirmity  recursively  discursively  disturbingly  concertedly  excursively  disconcertingly  incontrovertibly