In a direction midway between south and west. With reference to place, location, or relative position. Also followed by of.

The point of the horizon midway between south and west; (also) the direction of this; the compass point… Without definite article.

The point of the horizon midway between south and west; the south-west. to the south-westward (of): in a south-west direction (from).

= southwestward, n.