Source : Webster's Revised Unabridged Dictionary (1913)

Southwest \South`west\ (?; colloq. sou"-.), n.
   The point of the compass equally from the south and the west;
   the southwest part or region.

Southwest \South`west"\, a.
   Pertaining to, or in the direction of, the southwest;
   proceeding toward the southwest; coming from the southwest;
   as, a southwest wind.

Source : WordNet®

southwest
     adj 1: coming from the southwest; "the winds are southwesterly"
            [syn: {southwesterly}]
     2: situated in or oriented toward the southwest [syn: {southwestern},
         {southwesterly}]

southwest
     n 1: the compass point midway between south and west; at 225
          degrees [syn: {sou'-west}, {SW}]
     2: the southwestern region of the United States [syn: {southwestern
        United States}]

southwest
     adv : to, toward, or in the southwest [syn: {south-west}, {sou'west}]