The Collaborative International Dictionary of English v.0.48:

Differ \Dif"fer\, v. t.
   To cause to be different or unlike; to set at variance. [R.]
   [1913 Webster]

         But something 'ts that differs thee and me. --Cowley.
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The Collaborative International Dictionary of English v.0.48:

Differ \Dif"fer\, v. i. [imp. & p. p. Differed; p. pr. & vb.
   n. Differing.] [L. differre; dif- = dis- + ferre to bear,
   carry: cf. F. diff['e]rer. See 1st Bear, and cf. Defer,
   Delay.]
   1. To be or stand apart; to disagree; to be unlike; to be
      distinguished; -- with from.
      [1913 Webster]

            One star differeth from another star in glory. --1
                                                  Cor. xv. 41.
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            Minds differ, as rivers differ.       --Macaulay.
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   2. To be of unlike or opposite opinion; to disagree in
      sentiment; -- often with from or with.
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   3. To have a difference, cause of variance, or quarrel; to
      dispute; to contend.
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            We 'll never differ with a crowded pit. --Rowe.

   Syn: To vary; disagree; dissent; dispute; contend; oppose;
        wrangle.

   Usage: -- To Differ with, Differ from. Both differ from
          and differ with are used in reference to opinions; as,
          "I differ from you or with you in that opinion." In
          all other cases, expressing simple unlikeness, differ
          from is used; as, these two persons or things differ
          entirely from each other.
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                Severely punished, not for differing from us in
                opinion, but for committing a nuisance.
                                                  --Macaulay.
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                Davidson, whom on a former occasion we quoted,
                to differ from him.               --M. Arnold.
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                Much as I differ from him concerning an
                essential part of the historic basis of
                religion.                         --Gladstone.
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                I differ with the honorable gentleman on that
                point.                            --Brougham.
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                If the honorable gentleman differs with me on
                that subject, I differ as heartily with him, and
                shall always rejoice to differ.   --Canning.
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WordNet (r) 3.0 (2006):

differ
    v 1: be different; "These two tests differ in only one respect"
         [ant: be, equal]
    2: be of different opinions; "I beg to differ!"; "She disagrees
       with her husband on many questions" [syn: disagree,
       differ, dissent, take issue] [ant: agree, concord,
       concur, hold]

Moby Thesaurus II by Grady Ward, 1.0:

95 Moby Thesaurus words for "differ":
   agree to differ, agree to disagree, altercate, argue,
   be at cross-purposes, be at variance, be distinct,
   be distinguished, be in dissent, bear no resemblance,
   beg to differ, bicker, brawl, break, break off, break up, broil,
   clash, clash with, collide, conflict, conflict with, contradict,
   contrast, contrast with, counter, debate, depart, depart from,
   deviate, deviate from, differ in opinion, differentiate, disaccord,
   disaccord with, disagree, disagree with, discord, discord with,
   dispute, dissent, dissent from, disunify, divaricate,
   divaricate from, diverge, diverge from, diversify, divide,
   divide on, drop out, fall out, feud, fight, flite, have words,
   hold opposite views, jangle, jar, jar with, join issue, jostle,
   mismatch, mismate, misunderstand one another, negate,
   not accord with, not agree, not compare with, not get along,
   not look like, not square with, object, oppose, part company,
   protest against, pull different ways, quarrel, relieve, secede,
   set to, spar, spat, squabble, stand apart, stand over against,
   take exception, take issue, tiff, variate, variegate, vary,
   withdraw, withhold assent, wrangle