blindside

(automotive) A driver's field of blindness around an automobile; the side areas behind the driver.

(rail transport) A tram/train driver's field of blindness around a tram (trolley/streetcar) or a train; the side areas behind the tram/train driver.

(figuratively) A person's weak point.

(rugby) The space on the side of the pitch with the shorter distance between the breakdown/set piece and the touchline; compare openside.

(rugby union) The blindside flanker, a position in rugby union, usually number 6.