The Collaborative International Dictionary of English v.0.48:

Countenance \Coun"te*nance\ (koun"t[-e]*nans), n. [OE.
   contenance, countenaunce, demeanor, composure, F. contenance
   demeanor, fr. L. continentia continence, LL. also, demeanor,
   fr. L. continere to hold together, repress, contain. See
   Contain, and cf. Continence.]
   1. Appearance or expression of the face; look; aspect; mien.
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            So spake the Son, and into terror changed
            His countenance.                      --Milton.
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   2. The face; the features.
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            In countenance somewhat doth resemble you. --Shak.
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   3. Approving or encouraging aspect of face; hence, favor,
      good will, support; aid; encouragement.
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            Thou hast made him . . . glad with thy countenance.
                                                  --Ps. xxi. 6.
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            This is the magistrate's peculiar province, to give
            countenance to piety and virtue, and to rebuke vice.
                                                  --Atterbury.
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   4. Superficial appearance; show; pretense. [Obs.]
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            The election being done, he made countenance of
            great discontent thereat.             --Ascham.
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   In countenance, in an assured condition or aspect; free
      from shame or dismay. "It puts the learned in countenance,
      and gives them a place among the fashionable part of
      mankind." --Addison.

   Out of countenance, not bold or assured; confounded;
      abashed. "Their best friends were out of countenance,
      because they found that the imputations . . . were well
      grounded." --Clarendon.

   To keep the countenance, to preserve a composed or natural
      look, undisturbed by passion or emotion. --Swift.
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The Collaborative International Dictionary of English v.0.48:

Countenance \Coun"te*nance\ (koun"t?-nans), v. t. [imp. & p. p.
   Countenanced (-nanst); p. pr. & vb. n. Countenancing.]
   1. To encourage; to favor; to approve; to aid; to abet.
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            This conceit, though countenanced by learned men, is
            not made out either by experience or reason. --Sir
                                                  T. Browne.
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            Error supports custom, custom countenances error.
                                                  --Milton.
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   2. To make a show of; to pretend. [Obs.]
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            Which to these ladies love did countenance.
                                                  --Spenser.
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WordNet (r) 3.0 (2006):

countenance
    n 1: the appearance conveyed by a person's face; "a pleasant
         countenance"; "a stern visage" [syn: countenance,
         visage]
    2: formal and explicit approval; "a Democrat usually gets the
       union's endorsement" [syn: sanction, countenance,
       endorsement, indorsement, warrant, imprimatur]
    3: the human face (`kisser' and `smiler' and `mug' are informal
       terms for `face' and `phiz' is British) [syn: countenance,
       physiognomy, phiz, visage, kisser, smiler, mug]
    v 1: consent to, give permission; "She permitted her son to
         visit her estranged husband"; "I won't let the police
         search her basement"; "I cannot allow you to see your exam"
         [syn: permit, allow, let, countenance] [ant:
         disallow, forbid, interdict, nix, prohibit,
         proscribe, veto]