fēng​mǎ​niú​bù​xiāng​gān

totally unrelated

  1. wind
    wind; the movement of air caused by differences in air pressure
  2. horse
    horse; any animal of the horse family; large mammal used for riding, pulling carts, or farm work
  3. ox
    ox; cow; bull; cattle; any of various bovine animals
  4. irrelevant
    to have nothing to do with each other; to be unrelated