The Collaborative International Dictionary of English v.0.48:

Neglect \Neg*lect"\, v. t. [imp. & p. p. Neglected; p. pr. &
   vb. n. Neglecting.] [L. neglectus, p. p. of neglegere
   (negligere) to disregard, neglect, the literal sense prob.
   being, not to pick up; nec not, nor (fr. ne not + -que, a
   particle akin to Goth. -h, -uh, and prob. to E. who; cf.
   Goth. nih nor) + L. legere to pick up, gather. See No,
   adv., Legend, Who.]
   1. Not to attend to with due care or attention; to forbear
      one's duty in regard to; to allow to pass unimproved,
      unheeded, undone, etc.; to omit; to disregard; to slight;
      as, to neglect duty or business; to neglect to pay debts.
      [1913 Webster]

            I hope
            My absence doth neglect no great designs. --Shak.
      [1913 Webster]

            This, my long suffering and my day of grace,
            Those who neglect and scorn shall never taste.
                                                  --Milton.
      [1913 Webster]

   2. To omit to notice; to forbear to treat with attention or
      respect; to slight; as, to neglect strangers.
      [1913 Webster]

   Syn: To slight; overlook; disregard; disesteem; contemn. See
        Slight.
        [1913 Webster]

WordNet (r) 3.0 (2006):

neglected
    adj 1: disregarded; "his cries were unheeded"; "Shaw's neglected
           one-act comedy, `A Village Wooing'"; "her ignored advice"
           [syn: ignored, neglected, unheeded]
    2: lacking a caretaker; "a neglected child"; "many casualties
       were lying unattended" [syn: neglected, unattended]

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "neglected":
   abandoned, deserted, disregarded, forgotten, half-done, ignored,
   ill-requited, ill-rewarded, laid aside, left undone, missed,
   omitted, overlooked, passed by, passed over, passed up,
   pigeonholed, put aside, run-down, shunted, sidelined, sidetracked,
   slighted, unaccomplished, unachieved, unacknowledged, unasked,
   unattained, unattended to, uncared-for, unchaperoned, uncompleted,
   unconsidered, unconsummated, uncredited, undischarged, undone,
   unexecuted, unfairly neglected, unfinished, unfulfilled, unheeded,
   unperformed, unrealized, unrecognized, unregarded, unrequited,
   unrewarded, unsolicited, untended, unthanked, unwatched