The Collaborative International Dictionary of English v.0.48:

Speculative \Spec"u*la*tive\ (sp[e^]k"[-u]*l[.a]*t[i^]v), a.
   [Cf. F. sp['e]culatif, L. speculativus.]
   1. Given to speculation; contemplative.
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            The mind of man being by nature speculative.
                                                  --Hooker.
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   2. Involving, or formed by, speculation; ideal; theoretical;
      not established by demonstration. --Cudworth.
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   3. Of or pertaining to vision; also, prying; inquisitive;
      curious. [R.] --Bacon.
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   4. Of or pertaining to speculation in land, goods, shares,
      etc.; as, a speculative dealer or enterprise.
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            The speculative merchant exercises no one regular,
            established, or well-known branch of business. --A.
                                                  Smith.
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   5. (Finance) More risky than typical investments; not
      investment grade.
      [PJC] -- Spec"u*la*tive*ly, adv. --
      Spec"u*la*tive*ness, n.
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WordNet (r) 3.0 (2006):

speculatively
    adv 1: with speculation; in a speculative manner; "he looked at
           her speculatively"