The Collaborative International Dictionary of English v.0.48:

Accredit \Ac*cred"it\, v. t. [imp. & p. p. Accredited; p. pr.
   & vb. n. Accrediting.] [F. accr['e]diter; [`a] (L. ad) +
   cr['e]dit credit. See Credit.]
   1. To put or bring into credit; to invest with credit or
      authority; to sanction.
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            His censure will . . . accredit his praises.
                                                  --Cowper.
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            These reasons . . . which accredit and fortify mine
            opinion.                              --Shelton.
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   2. To send with letters credential, as an ambassador, envoy,
      or diplomatic agent; to authorize, as a messenger or
      delegate.
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            Beton . . . was accredited to the Court of France.
                                                  --Froude.
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   3. To believe; to credit; to put trust in.
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            The version of early Roman history which was
            accredited in the fifth century.      --Sir G. C.
                                                  Lewis.
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            He accredited and repeated stories of apparitions
            and witchcraft.                       --Southey.
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   4. To credit; to vouch for or consider (some one) as doing
      something, or (something) as belonging to some one.
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   To accredit (one) with (something), to attribute
      something to him; as, Mr. Clay was accredited with these
      views; they accredit him with a wise saying.
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WordNet (r) 3.0 (2006):

accredit
    v 1: grant credentials to; "The Regents officially recognized
         the new educational institution"; "recognize an academic
         degree" [syn: accredit, recognize, recognise]
    2: provide or send (envoys or embassadors) with official
       credentials
    3: ascribe an achievement to; "She was not properly credited in
       the program" [syn: accredit, credit]

Moby Thesaurus II by Grady Ward, 1.0:

109 Moby Thesaurus words for "accredit":
   OK, accept, account for, accredit with, accrete to, acknowledge,
   affirm, amen, apply to, approve, ascribe to, assign, assign to,
   attach to, attest, attribute, attribute to, authenticate,
   authorize, autograph, blame, blame for, blame on, bring home to,
   certify, charge, charge on, charge to, charter, commend,
   commission, commit, confess, confirm, connect with, consign,
   cosign, countersign, credit, credit with, delegate, depute,
   deputize, detach, detail, devolute, devolve, devolve upon, empower,
   enable, endorse, entrust, fasten upon, father upon, fix on,
   fix upon, give in charge, give permission, give the go-ahead,
   give the imprimatur, give thumbs up, hang on, impute, impute to,
   initial, introduce, lay, lay to, license, mission, notarize, pass,
   pass on, pass upon, permit, pin on, pinpoint, place upon, point to,
   post, present, ratify, recommend, refer, refer to, rubber stamp,
   saddle on, saddle with, sanction, say amen to, seal, second,
   send out, set down to, settle upon, sign, sign and seal,
   subscribe to, support, swear and affirm, swear to, transfer,
   undersign, underwrite, validate, visa, vise, vouch for, warrant