Here's what rhymes with semilength.
                        
                        
                    
                                Words that almost rhyme with semilength
lens  tenth  sense  hence  dense  thence  whence  fence  tense  tens  cleanse  gems  hens  pence  pens  dens  gens  glens  fens  hems  immense  offence  offense  stems  theorems  morphemes  harems  defence  defense  intense  commence  incense  pretense  sixpence  expense  dispense  suspense  condemns  condense  halfpence  recommence  twopence  recompense  commonsense  frankincense  length  death  health  wealth  breath  depth  breadth  neath  strength  stealth  shibboleth  twelfth  commonwealth