The Collaborative International Dictionary of English v.0.48:

Attitude \At"ti*tude\, n. [It. attitudine, LL. aptitudo, fr. L.
   aptus suited, fitted: cf. F. attitude. Cf. Aptitude.]
   1. (Paint. & Sculp.) The posture, action, or disposition of a
      figure or a statue.
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   2. The posture or position of a person or an animal, or the
      manner in which the parts of his body are disposed;
      position assumed or studied to serve a purpose; as, a
      threatening attitude; an attitude of entreaty.
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   3. Fig.: Position as indicating action, feeling, or mood; as,
      in times of trouble let a nation preserve a firm attitude;
      one's mental attitude in respect to religion.
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            The attitude of the country was rapidly changing.
                                                  --J. R. Green.
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   To strike an attitude, to take an attitude for mere effect.
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   Syn: Attitude, Posture.

   Usage: Both of these words describe the visible disposition
          of the limbs. Posture relates to their position
          merely; attitude refers to their fitness for some
          specific object. The object of an attitude is to set
          forth exhibit some internal feeling; as, attitude of
          wonder, of admiration, of grief, etc. It is,
          therefore, essentially and designedly expressive. Its
          object is the same with that of gesture; viz., to hold
          forth and represent. Posture has no such design. If we
          speak of posture in prayer, or the posture of
          devotion, it is only the natural disposition of the
          limbs, without any intention to show forth or exhibit.
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                'T is business of a painter in his choice of
                attitudes (positur[ae]) to foresee the effect
                and harmony of the lights and shadows. --Dryden.
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                Never to keep the body in the same posture half
                an hour at a time.                --Bacon.
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WordNet (r) 3.0 (2006):

attitude
    n 1: a complex mental state involving beliefs and feelings and
         values and dispositions to act in certain ways; "he had the
         attitude that work was fun" [syn: attitude, mental
         attitude]
    2: the arrangement of the body and its limbs; "he assumed an
       attitude of surrender" [syn: position, posture,
       attitude]
    3: a theatrical pose created for effect; "the actor struck just
       the right attitude"
    4: position of aircraft or spacecraft relative to a frame of
       reference (the horizon or direction of motion)

Moby Thesaurus II by Grady Ward, 1.0:

79 Moby Thesaurus words for "attitude":
   air, approach, aspect, assumption, azimuth, bearing, bearings,
   bent, bias, carriage, celestial navigation, climate of opinion,
   color, common belief, community sentiment, conceit, concept,
   conception, conclusion, consensus gentium, consideration,
   dead reckoning, demeanor, disposition, estimate, estimation, ethos,
   exposure, eye, feeling, fix, frontage, general belief, idea,
   impression, inclination, judgment, lay, leaning, lie, lights,
   line of position, mind, mystique, notion, observation, opinion,
   orientation, personal judgment, pilotage, point of view,
   popular belief, port, pose, position, position line, posture,
   predilection, prejudice, prepossession, presence, presumption,
   prevailing belief, public belief, public opinion, radio bearing,
   reaction, sentiment, set, sight, stance, stand, tendency, theory,
   thinking, thought, view, viewpoint, way of thinking