SW-the compass point midway between south and west; at 225 degrees. southwest, southwestward, sou'-west. compass point, point-any of 32 horizontal directions indicated on the card of a compass; he checked the point on his compass.W-the compass point midway between south and west; at 225 degrees. southwest, southwestward, sou'-west. compass point, point-any of 32 horizontal directions indicated on the card of a compass; he checked the point on his compass.