[1] : The Collaborative International Dictionary of English v.0.48

sag \sag\ sa^g, v. i. imp.  p. p. sagged; p. pr.  vb.
   n. sagging. akin to sw. sacka to settle, sink down, lg.
   sacken, d. zakken. cf. sink, v. i.
   1. to sink, in the middle, by its weight or under applied
      pressure, below a horizontal line or plane; as, a line or
      cable supported by its ends sags, though tightly drawn;
      the floor of a room sags; hence, to lean, give way, or
      settle from a vertical position; as, a building may sag
      one way or another; a door sags on its hinges.
      1913 webster

   2. fig.: to lose firmness or elasticity; to sink; to droop;
      to flag; to bend; to yield, as the mind or spirits, under
      the pressure of care, trouble, doubt, or the like; to be
      unsettled or unbalanced. r.
      1913 webster

            the mind i sway by, and the heart i bear,
            shall never sag with doubt nor shake with fear.
                                                  --shak.
      1913 webster

   3. to loiter in walking; to idle along; to drag or droop
      heavily.
      1913 webster

   to sag to leeward naut., to make much leeway by reason of
      the wind, sea, or current; to drift to leeward; -- said of
      a vessel. --totten.
      1913 webster
see also:
sagged sagging sink to sag to leeward 

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Leeward, definition of term: Leeward
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