The Collaborative International Dictionary of English v.0.48:

West \West\, n. [AS. west, adv.; akin to D. west, G. west,
   westen, OHG. westan, Icel. vestr, Sw. vest, vester, vestan,
   Dan. vest, vesten, and perhaps to L. vesper evening, Gr. ?.
   ????. Cf. Vesper, Visigoth.]
   [1913 Webster]
   1. The point in the heavens where the sun is seen to set at
      the equinox; or, the corresponding point on the earth;
      that one of the four cardinal points of the compass which
      is in a direction at right angles to that of north and
      south, and on the left hand of a person facing north; the
      point directly opposite to east.
      [1913 Webster]

            And fresh from the west is the free wind's breath.
                                                  --Bryant.
      [1913 Webster]

   2. A country, or region of country, which, with regard to
      some other country or region, is situated in the direction
      toward the west.
      [1913 Webster]

   3. Specifically:
      (a) The Westen hemisphere, or the New World so called, it
          having been discovered by sailing westward from
          Europe; the Occident.
      (b) (U. S. Hist. & Geog.) Formerly, that part of the
          United States west of the Alleghany mountains; now,
          commonly, the whole region west of the Mississippi
          river; esp., that part which is north of the Indian
          Territory, New Mexico, etc. Usually with the definite
          article.
          [1913 Webster]

   West by north, West by south, according to the notation
      of the mariner's compass, that point which lies 111/4[deg]
      to the north or south, respectively, of the point due
      west.

   West northwest, West southwest, that point which lies
      221/2[deg] to the north or south of west, or halfway
      between west and northwest or southwest, respectively. See
      Illust. of Compass.
      [1913 Webster]

WordNet (r) 3.0 (2006):

west northwest
    n 1: the compass point midway between west and northwest [syn:
         west northwest, WNW]