The Collaborative International Dictionary of English v.0.48:

Posture \Pos"ture\ (?; 135), n. [F., fr. L. positura, fr.
   ponere, positum, to place. See Position.]
   1. The position of the body; the situation or disposition of
      the several parts of the body with respect to each other,
      or for a particular purpose; especially (Fine Arts), the
      position of a figure with regard to the several principal
      members by which action is expressed; attitude.
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            Atalanta, the posture of whose limbs was so lively
            expressed . . . one would have sworn the very
            picture had run.                      --Sir P.
                                                  Sidney.
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            In most strange postures
            We have seen him set himself.         --Shak.
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            The posture of a poetic figure is a description of
            his heroes in the performance of such or such an
            action.                               --Dryden.
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   2. Place; position; situation. [Obs.] --Milton.
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            His [man's] noblest posture and station in this
            world.                                --Sir M. Hale.
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   3. State or condition, whether of external circumstances, or
      of internal feeling and will; disposition; mood; as, a
      posture of defense; the posture of affairs.
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            The several postures of his devout soul.
                                                  --Atterbury.
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   Syn: Attitude; position. See Attitude.
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The Collaborative International Dictionary of English v.0.48:

Posture \Pos"ture\ (?; 135), v. t. [imp. & p. p. Postured; p.
   pr. & vb. n. Posturing.]
   To place in a particular position or attitude; to dispose the
   parts of, with reference to a particular purpose; as, to
   posture one's self; to posture a model. --Howell.
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The Collaborative International Dictionary of English v.0.48:

Posture \Pos"ture\, v. i.
   1. To assume a particular posture or attitude; to contort the
      body into artificial attitudes, as an acrobat or
      contortionist; also, to pose.
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   2. Fig.: To assume a character; as, to posture as a saint.
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WordNet (r) 3.0 (2006):

posture
    n 1: the arrangement of the body and its limbs; "he assumed an
         attitude of surrender" [syn: position, posture,
         attitude]
    2: characteristic way of bearing one's body; "stood with good
       posture" [syn: carriage, bearing, posture]
    3: a rationalized mental attitude [syn: position, stance,
       posture]
    4: capability in terms of personnel and materiel that affect the
       capacity to fight a war; "we faced an army of great
       strength"; "politicians have neglected our military posture"
       [syn: military capability, military strength, strength,
       military posture, posture]
    v 1: behave affectedly or unnaturally in order to impress
         others; "Don't pay any attention to him--he is always
         posing to impress his peers!"; "She postured and made a
         total fool of herself" [syn: pose, posture]
    2: assume a posture as for artistic purposes; "We don't know the
       woman who posed for Leonardo so often" [syn: model, pose,
       sit, posture]