The Collaborative International Dictionary of English v.0.48:

Succor \Suc"cor\, v. t. [imp. & p. p. Succored; p. pr. & vb.
   n. Succoring.] [OE. socouren, OF. sucurre, soucourre,
   secorre, F. secourir, L. succurrere, succursum, to run under,
   run to the aid of, help, succor; sub under + currere to run.
   See Current.]
   To run to, or run to support; hence, to help or relieve when
   in difficulty, want, or distress; to assist and deliver from
   suffering; to relieve; as, to succor a besieged city.
   [Written also succour.]
   [1913 Webster]

         He is able to succor them that are tempted. --Heb. ii.
                                                  18.
   [1913 Webster]

   Syn: To aid; assist; relieve; deliver; help; comfort.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Succor \Suc"cor\, n. [OE. socours, sucurs, OF. sucurs, socors,
   secors, F. secours, L. succursus, fr. L. succurrere. See
   Succor, v. t.]
   1. Aid; help; assistance; esp., assistance that relieves and
      delivers from difficulty, want, or distress. "We beseech
      mercy and succor." --Chaucer.
      [1913 Webster]

            My noble father . . .
            Flying for succor to his servant Bannister. --Shak.
      [1913 Webster]

   2. The person or thing that brings relief.
      [1913 Webster]

            This mighty succor, which made glad the foe.
                                                  --Dryden.
      [1913 Webster]

WordNet (r) 3.0 (2006):

succor
    n 1: assistance in time of difficulty; "the contributions
         provided some relief for the victims" [syn: relief,
         succor, succour, ministration]
    v 1: help in a difficult situation [syn: succor, succour]

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "succor":
   abet, aid, alterative, analeptic, assist, assistance, avail,
   bail out, balm, balsam, bear a hand, befriend, benefit, comfort,
   corrective, cure, do good, doctor, ease, favor, give a boost,
   give a hand, give a lift, give help, good offices, hand,
   healing agent, healing quality, help, lend a hand, lend one aid,
   lift, maintenance, ministration, ministry, nourishment, office,
   offices, prescription, proffer aid, protect, protection, rally,
   receipt, recipe, reclaim, redeem, relief, relieve,
   remedial measure, remedy, render assistance, rescue, restorative,
   restore, resuscitate, revive, save, service, set up,
   sovereign remedy, specific, specific remedy, support, sustenance,
   take in tow, therapy