The Collaborative International Dictionary of English v.0.48:

Impute \Im*pute"\, v. t. [imp. & p. p. Imputed; p. pr. & vb.
   n. Imputing.] [F. imputer, L. imputare to bring into the
   reckoning, charge, impute; pref. im- in + putare to reckon,
   think. See Putative.]
   [1913 Webster]
   1. To charge; to ascribe; to attribute; to set to the account
      of; to charge to one as the author, responsible
      originator, or possessor; -- generally in a bad sense.
      [1913 Webster]

            Nor you, ye proud, impute to these the fault,
            If memory o'er their tomb no trophies raise. --Gray.
      [1913 Webster]

            One vice of a darker shade was imputed to him --
            envy.                                 --Macaulay.
      [1913 Webster]

   2. (Theol.) To adjudge as one's own (the sin or
      righteousness) of another; as, the righteousness of Christ
      is imputed to us.
      [1913 Webster]

            It was imputed to him for righteousness. --Rom. iv.
                                                  22.
      [1913 Webster]

            They merit
            Imputed shall absolve them who renounce
            Their own, both righteous and unrighteous deeds.
                                                  --Milton.
      [1913 Webster]

   3. To take account of; to consider; to regard. [R.]
      [1913 Webster]

            If we impute this last humiliation as the cause of
            his death.                            --Gibbon.

   Syn: To ascribe; attribute; charge; reckon; consider; imply;
        insinuate; refer. See Ascribe.
        [1913 Webster]

WordNet (r) 3.0 (2006):

impute
    v 1: attribute or credit to; "We attributed this quotation to
         Shakespeare"; "People impute great cleverness to cats"
         [syn: impute, ascribe, assign, attribute]
    2: attribute (responsibility or fault) to a cause or source;
       "The teacher imputed the student's failure to his
       nervousness"

Moby Thesaurus II by Grady Ward, 1.0:

55 Moby Thesaurus words for "impute":
   accredit, accuse, adduce, allege, apply, arraign, article, ascribe,
   assign, attach, attribute, book, bring accusation, bring charges,
   bring to book, charge, cite, complain, credit, denounce,
   denunciate, fasten on, fasten upon, finger, give,
   hang something on, hint, hint at, impeach, imply, indict,
   inform against, inform on, insinuate, intimate, lay, lay charges,
   lodge a complaint, lodge a plaint, pin on, place, prefer charges,
   press charges, put, put on report, refer, report, reproach,
   set down to, suggest, take to task, task, taunt with, tax, twit