The Collaborative International Dictionary of English v.0.48:

Creditable \Cred"it*a*ble\ (-?-b'l), a.
   1. Worthy of belief. [Obs.]
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            Divers creditable witnesses deposed.  --Ludlow.
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   2. Deserving or possessing reputation or esteem; reputable;
      estimable.
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            This gentleman was born of creditable parents.
                                                  --Goldsmith.
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   3. Bringing credit, reputation, or honor; honorable; as, such
      conduct is highly creditable to him. --Macaulay.
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            He settled him in a good creditable way of living.
                                                  --Arbuthnot.
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WordNet (r) 3.0 (2006):

creditable
    adj 1: worthy of often limited commendation; "the student's
           effort on the essay--though not outstanding--was
           creditable"