Here's what rhymes with apprehendendum.
                        
                        
                    
                                addendum  Words that almost rhyme with apprehendendum
deaden  leaden  redden  weapon  threaten  denim  bedlam  seldom  venom  harem  plenum  vellum  velum  jetsam  phenom  welcome  rectum  cerebellum  flagellum  spectrum  momentum  referendum  septum  unwelcome  antebellum  antiserum  interregnum  plectrum