BACK (5)

Back, v. i. 1. 1. To move or go backward; as, the horse refuses to back.
2. 2. (Naut.) To change from one quarter to another by a course opposite to that of the sun; — used of the wind.
3. 3. (Sporting) To stand still behind another dog which has pointed; — said of a dog.
To back and fill, to manage the sails of a ship so that the wind strikes them alternately in front and behind, in order to keep the ship in the middle of a river or channel while the current or tide carries the vessel against the wind. Hence: (Fig.) To take opposite positions alternately; to assert and deny. — To back out, To back down, to retreat or withdraw from a promise, engagement, or contest; to recede. Cleon at first . . . was willing to go; but, finding that he was in earnest, he tried to back out. Jowett (Thucyd. )