The Collaborative International Dictionary of English v.0.48:

Obstinate \Ob"sti*nate\, a. [L. obstinatus, p. p. of obstinare
   to set about a thing with firmness, to persist in; ob (see
   Ob-) + a word from the root of stare to stand. See Stand,
   and cf. Destine.]
   1. Pertinaciously adhering to an opinion, purpose, or course;
      persistent; not yielding to reason, arguments, or other
      means; stubborn; pertinacious; -- usually implying
      unreasonableness.
      [1913 Webster]

            I have known great cures done by obstinate
            resolution of drinking no wine.       --Sir W.
                                                  Temple.
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            No ass so meek, no ass so obstinate.  --Pope.
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            Of sense and outward things.          --Wordsworth.
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   2. Not yielding; not easily subdued or removed; as, obstinate
      fever; obstinate obstructions.
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   Syn: Stubborn; inflexible; immovable; firm; pertinacious;
        persistent; headstrong; opinionated; unyielding;
        refractory; contumacious. See Stubborn.
        [1913 Webster] -- Ob"sti*nate*ly, adv. --
        Ob"sti*nate*ness, n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

obstinately
    adv 1: in a stubborn unregenerate manner; "she remained
           stubbornly in the same position" [syn: stubbornly,
           pig-headedly, obdurately, mulishly, obstinately,
           cussedly]