Here's what rhymes with knowwho.
                        
                        
                    
                                who  shoe  zu  shew  su  sue  vous  fu  zoo  hu  seu  shu  sou  vu  feu  shou  thu  vou  shoo  thew  to  you  do  two  new  through  too  few  view  due  knew  du  u  threw  coup  flew  qu  dew  hue  lieu  tu  chew  deux  flue  lu  rue  slew  stew  bu  flu  ju  jus  ku  loo  mu  nu  peu  pu  thru  woo  yew  yu  boo  chou  chu  coo  cou  doo  ewe  fue  gu  hew  ru  shrew  tue  tzu  vue  wou  wu  goo  moo  pooh  poo  gnu  roux  slue  whew  phew  true  blue  drew  grew  que  crew  pursue  blew  q  screw  anew  clue  cue  glue  queue  cu  ensue  adieu  ado  brew  overdue  pew  skew  beaucoup  eschew  mieux  sprue  vnto  clew  mew  overdo  strew  halloo  spew  valuer  zebu  kazoo  overshoe  wazoo  achoo  into  review  overview  avenue  canoe  renew  undue  accrue  subdue  taboo  undo  untrue  jusqu  overthrew  piu  tattoo  outdo  revue  shampoo  sinew  askew  imbue  redo  endue  foreknew  indue  muumuu  overflew  overdrew  overgrew  booboo  atishoo  interview  revenue  hitherto  residue  withdrew  bamboo  debut  rendezvous  kangaroo  outgrew  ballyhoo  honeydew  fondue  marabou  bestrew  prevue  regrew  retinue  caribou  construe  cockatoo  bugaboo  peekaboo  buckaroo  superglue  hullabaloo  barbecue  misconstrue  barbeque