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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The Collaborative International Dictionary of English v.0.48:

Why \Why\, adv. [OE. whi, why, AS. hw[imac], hw?, instrumental
   case of hw[=a], hw[ae]t; akin to Icel. hv[imac] why, Dan. &
   Sw. hvi; cf. Goth. hw?. ?. See Who.]
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   1. For what cause, reason, or purpose; on what account;
      wherefore; -- used interrogatively. See the Note under
      What, pron., 1.
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            Turn ye, turn ye from your evil ways; for why will
            ye die, O house of Israel?            --Ezek.
                                                  xxxiii. 11.
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   2. For which; on account of which; -- used relatively.
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            No ground of enmity between us known
            Why he should mean me ill or seek to harm. --Milton.
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            Turn the discourse; I have a reason why
            I would not have you speak so tenderly. --Dryden.
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   3. The reason or cause for which; that on account of which;
      on what account; as, I know not why he left town so
      suddenly; -- used as a compound relative.
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   Note: Why is sometimes used as an interjection or an
         expletive in expression of surprise or content at a
         turn of affairs; used also in calling. "Why, Jessica!"
         --Shak.
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               If her chill heart I can not move,
               Why, I'll enjoy the very love.     --Cowley.
         [1913 Webster] Sometimes, also, it is used as a noun.
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               The how and the why and the where. --Goldsmith.
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   For why, because; why. See Forwhy. [Obs. or Colloq.]
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