The Collaborative International Dictionary of English v.0.48:

Forsake \For*sake"\, v. t. [imp. Forsook; p. p. Forsaken; p.
   pr. & vb. n. Forsaking.] [AS. forsacan to oppose, refuse;
   for- + sacan to contend, strive; akin to Goth. sakan. See
   For-, and Sake.]
   1. To quit or leave entirely; to desert; to abandon; to
      depart or withdraw from; to leave; as, false friends and
      flatterers forsake us in adversity.
      [1913 Webster]

            If his children forsake my law, and walk not in my
            judgments.                            --Ps. lxxxix.
                                                  30.
      [1913 Webster]

   2. To renounce; to reject; to refuse.
      [1913 Webster]

            If you forsake the offer of their love. --Shak.

   Syn: To abandon; quit; desert; fail; relinquish; give up;
        renounce; reject. See Abandon.
        [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "forsaken":
   abandoned, available, cast-off, castaway, defenseless, derelict,
   deserted, desolate, discarded, disowned, disused, fatherless,
   forlorn, free, friendless, godforsaken, helpless, homeless,
   jettisoned, jilted, kithless, left, loveless, lovelorn, marooned,
   motherless, open, outcast, outside the gates, outside the pale,
   rejected, solitary, spurned, tenantless, unbeloved, uncherished,
   uncouth, unfilled, unfriended, uninhabited, unloved, unmanned,
   unoccupied, unpeopled, unpopulated, unstaffed, untaken, untenanted,
   untended, vacant