The Collaborative International Dictionary of English v.0.48:

For \For\, conj.
   1. Because; by reason that; for that; indicating, in Old
      English, the reason of anything.
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            And for of long that way had walk['e]d none,
            The vault was hid with plants and bushes hoar.
                                                  --Fairfax.
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            And Heaven defend your good souls, that you think
            I will your serious and great business scant,
            For she with me.                      --Shak.
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   2. Since; because; introducing a reason of something before
      advanced, a cause, motive, explanation, justification, or
      the like, of an action related or a statement made. It is
      logically nearly equivalent to since, or because, but
      connects less closely, and is sometimes used as a very
      general introduction to something suggested by what has
      gone before.
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            Give thanks unto the Lord; for he is good; for his
            mercy endureth forever.               --Ps. cxxxvi.
                                                  1.
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            Heaven doth with us as we with torches do,
            Not light them for themselves; for if our virtues
            Did not go forth of us, 't were all alike
            As if we had them not.                --Shak.
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   For because, because. [Obs.] "Nor for because they set less
      store by their own citizens." --Robynson (More's Utopia).

   For why.
      (a) Why; for that reason; wherefore. [Obs.]
      (b) Because. [Obs.] See Forwhy.

   Syn: See Because.
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