Opposite words for metaphor:
chronicle, history, record, fact, narrative.
Usage samples:
  1. To abandon the metaphor, man will determine by the use of his reason what he wishes life to be; he will choose the highest forms of it to which he can attain.
    "The Book of Life: Vol. I Mind and Body; Vol. II Love and Society", Upton Sinclair.
  2. " Your metaphor, Mac, suggests a picture.
    "Skinner's Dress Suit", Henry Irving Dodge.
  3. Not a whiff of metaphor or extravagance about that statement, Joan.
    "A Son of the Immortals", Louis Tracy.
  4. They both laughed a little at Louisa's mixed metaphor and the laughter cleared away the last trace of the tears.
    "Rainbow Hill", Josephine Lawrence.