Cleanness (Middle English: Clannesse) is a Middle English alliterative poem written in the late 14th century. Its unknown author, designated the Pearl poet or Gawain poet, also appears, on the basis of dialect and stylistic evidence, to be the author of Sir Gawain and the Green Knight, Pearl, and Patience, and may have composed St. Erkenwald. The poem is found solely in the Pearl manuscript, Cotton Nero A x. That manuscript also contains Pearl, Patience, and Sir Gawain and the Green Knight.