The Collaborative International Dictionary of English v.0.48:

Become \Be*come"\, v. i. [imp. Became; p. p. Become; p. pr.
   & vb. n. Becoming.] [OE. bicumen, becumen, AS. becuman to
   come to, to happen; akin to D. bekomen, OHG.a piqu["e]man,
   Goth. biquiman to come upon, G. bekommen to get, suit. See
   Be-, and Come.]
   1. To pass from one state to another; to enter into some
      state or condition, by a change from another state, or by
      assuming or receiving new properties or qualities,
      additional matter, or a new character.
      [1913 Webster]

            The Lord God . . . breathed into his nostrils the
            breath of life; and man became a living soul. --Gen.
                                                  ii. 7.
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            That error now which is become my crime. --Milton.
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   2. To come; to get. [Obs.]
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            But, madam, where is Warwick then become! --Shak.
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   To become of, to be the present state or place of; to be
      the fate of; to be the end of; to be the final or
      subsequent condition of.
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            What is then become of so huge a multitude? --Sir W.
                                                  Raleigh.
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The Collaborative International Dictionary of English v.0.48:

Become \Be*come"\, v. t.
   To suit or be suitable to; to be congruous with; to befit; to
   accord with, in character or circumstances; to be worthy of,
   or proper for; to cause to appear well; -- said of persons
   and things.
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         It becomes me so to speak of so excellent a poet.
                                                  --Dryden.
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         I have known persons so anxious to have their dress
         become them, as to convert it, at length, into their
         proper self, and thus actually to become the dress.
                                                  --Coleridge.
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WordNet (r) 3.0 (2006):

become
    v 1: enter or assume a certain state or condition; "He became
         annoyed when he heard the bad news"; "It must be getting
         more serious"; "her face went red with anger"; "She went
         into ecstasy"; "Get going!" [syn: become, go, get]
    2: undergo a change or development; "The water turned into ice";
       "Her former friend became her worst enemy"; "He turned
       traitor" [syn: become, turn]
    3: come into existence; "What becomes has duration"
    4: enhance the appearance of; "Mourning becomes Electra"; "This
       behavior doesn't suit you!" [syn: become, suit]

Moby Thesaurus II by Grady Ward, 1.0:

81 Moby Thesaurus words for "become":
   adorn, agree with, alter into, arise, assimilate to, be born,
   be bound, be changed, be converted into, be obligated, be obliged,
   become of, befit, behoove, beseem, break out, bring to,
   burst forth, change, change into, change over, come, come forth,
   come of, come out, come over, come round to, come to be, convert,
   crop up, do over, enhance, erupt, evolve into, fall into, fit, get,
   get to be, go, go with, grace, grow, have origin, irrupt, issue,
   issue forth, lapse into, make, make over, melt into, mount,
   naturalize, open into, originate, owe it to, pass into, reconvert,
   reduce to, render, resolve into, reverse, ripen into, rise, run,
   run into, settle into, shift, shift into, soar, spring up, suit,
   switch, switch over, take birth, take rise, transform, turn,
   turn back, turn into, turn to, wax