HOUYHNHNMS, ho͞o-ĭn′’mz or ho͞o′ĭn’mz. An imaginary nation of horses, of highly advanced civilization, gifted with reason and without passions, which Gulliver visits, in the fourth part of Swift's Gulliver's Travels. Their nature is supposed in the story to be as far superior to that of humanity as it is inferior in actual life.