The Collaborative International Dictionary of English v.0.48:

Suffer \Suf"fer\, v. i.
   1. To feel or undergo pain of body or mind; to bear what is
      inconvenient; as, we suffer from pain, sickness, or
      sorrow; we suffer with anxiety.
      [1913 Webster]

            O well for him whose will is strong!
            He suffers, but he will not suffer long. --Tennyson.
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   2. To undergo punishment; specifically, to undergo the
      penalty of death.
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            The father was first condemned to suffer upon a day
            appointed, and the son afterwards the day following.
                                                  --Clarendon.
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   3. To be injured; to sustain loss or damage.
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            Public business suffers by private infirmities.
                                                  --Sir W.
                                                  Temple.
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The Collaborative International Dictionary of English v.0.48:

Suffer \Suf"fer\, v. t. [imp. & p. p. Suffered; p. pr. & vb.
   n. Suffering.] [OE. suffren, soffren, OF. sufrir, sofrir,
   F. souffrir, (assumed) LL. sofferire, for L. sufferre; sub
   under + ferre to bear, akin to E. bear. See Bear to
   support.]
   1. To feel, or endure, with pain, annoyance, etc.; to submit
      to with distress or grief; to undergo; as, to suffer pain
      of body, or grief of mind.
      [1913 Webster]

   2. To endure or undergo without sinking; to support; to
      sustain; to bear up under.
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            Our spirit and strength entire,
            Strongly to suffer and support our pains. --Milton.
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   3. To undergo; to be affected by; to sustain; to experience;
      as, most substances suffer a change when long exposed to
      air and moisture; to suffer loss or damage.
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            If your more ponderous and settled project
            May suffer alteration.                --Shak.
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   4. To allow; to permit; not to forbid or hinder; to tolerate.
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            Thou shalt in any wise rebuke thy neighbour, and not
            suffer sin upon him.                  --Lev. xix.
                                                  17.
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            I suffer them to enter and possess.   --Milton.
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   Syn: To permit; bear; endure; support; sustain; allow; admit;
        tolerate. See Permit.
        [1913 Webster]

WordNet (r) 3.0 (2006):

suffer
    v 1: undergo or be subjected to; "He suffered the penalty";
         "Many saints suffered martyrdom" [syn: suffer, endure]
         [ant: enjoy]
    2: undergo (as of injuries and illnesses); "She suffered a
       fracture in the accident"; "He had an insulin shock after
       eating three candy bars"; "She got a bruise on her leg"; "He
       got his arm broken in the scuffle" [syn: suffer, sustain,
       have, get]
    3: experience (emotional) pain; "Every time her husband gets
       drunk, she suffers"
    4: put up with something or somebody unpleasant; "I cannot bear
       his constant criticism"; "The new secretary had to endure a
       lot of unprofessional remarks"; "he learned to tolerate the
       heat"; "She stuck out two years in a miserable marriage"
       [syn: digest, endure, stick out, stomach, bear,
       stand, tolerate, support, brook, abide, suffer,
       put up]
    5: get worse; "His grades suffered"
    6: feel pain or be in pain [syn: suffer, hurt] [ant: be
       well]
    7: feel physical pain; "Were you hurting after the accident?"
       [syn: hurt, ache, suffer]
    8: feel unwell or uncomfortable; "She is suffering from the hot
       weather"
    9: be given to; "She suffers from a tendency to talk too much"
    10: undergo or suffer; "meet a violent death"; "suffer a
        terrible fate" [syn: suffer, meet]
    11: be set at a disadvantage; "This author really suffers in
        translation" [syn: suffer, lose]

Moby Thesaurus II by Grady Ward, 1.0:

110 Moby Thesaurus words for "suffer":
   abide, abide with, accept, ache, acquiesce, admit, agonize, ail,
   allow, anguish, be affected with, be doubly punished,
   be exposed to, be punished, be subjected to, bear, bear with, bide,
   blanch, bleed, blench, blink at, bow, brave, brook, catch it,
   complain of, condone, connive at, countenance, decline,
   deteriorate, diminish, encounter, endure, experience, fall off,
   feel, feel ill, feel pain, feel the pangs, get it, go down,
   go hard with, go through, grimace, grin and abide, hang in,
   hang in there, hang tough, have, have a misery, hear of, humor,
   hurt, indulge, know, labor under, leave, let, live through, lump,
   lump it, meet, meet up with, meet with, overlook, pain,
   pass through, pay, permit, persevere, pound, put up with, receive,
   run up against, see, shoot, shrink, smart, spend, stand, stand for,
   stand under, stick, stomach, submit, submit to, suffer anguish,
   suffer for, suffer the consequences, support, sustain, swallow,
   sweat, take, take up with, taste, thrill, throb, tingle, tolerate,
   twinge, twitch, undergo, wince, wink at, withstand, writhe,
   yield