The Collaborative International Dictionary of English v.0.48:

Cheer \Cheer\, v. t. [imp. & p. p. Cheered (ch[=e]rd); p. pr.
   & vb. n. cheering.]
   1. To cause to rejoice; to gladden; to make cheerful; --
      often with up. --Cowpe.
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   2. To infuse life, courage, animation, or hope, into; to
      inspirit; to solace or comfort.
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            The proud he tamed, the penitent he cheered.
                                                  --Dryden.
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   3. To salute or applaud with cheers; to urge on by cheers;
      as, to cheer hounds in a chase.
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   To cheer ship, to salute a passing ship by cheers of
      sailors stationed in the rigging.

   Syn: To gladden; encourage; inspirit; comfort; console;
        enliven; refresh; exhilarate; animate; applaud.
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The Collaborative International Dictionary of English v.0.48:

Cheer \Cheer\ (ch[=e]r), n. [OE. chere face, welcome, cheer, OF.
   chiere, F. ch[`e]re, fr. LL. cara face, Gr. ka`ra head; akin
   to Skr. [,c]iras, L. cerebrum brain, G. hirn, and E.
   cranium.]
   1. The face; the countenance or its expression. [Obs.] "Sweat
      of thy cheer." --Wyclif.
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   2. Feeling; spirit; state of mind or heart.
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            Be of good cheer.                     --Matt. ix. 2.
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            The parents . . . fled away with heavy cheer.
                                                  --Holland.
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   3. Gayety; mirth; cheerfulness; animation.
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            I have not that alacrity of spirit,
            Nor cheer of mind, that I was wont to have. --Shak.
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   1. That which promotes good spirits or cheerfulness;
      provisions prepared for a feast; entertainment; as, a
      table loaded with good cheer.
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   5. A shout, hurrah, or acclamation, expressing joy
      enthusiasm, applause, favor, etc.
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            Welcome her, thundering cheer of the street.
                                                  --Tennyson.
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   What cheer? How do you fare? What is there that is
      cheering?
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The Collaborative International Dictionary of English v.0.48:

Cheer \Cheer\, v. i.
   1. To grow cheerful; to become gladsome or joyous; -- usually
      with up.
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            At sight of thee my gloomy soul cheers up. --A.
                                                  Philips.
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   2. To be in any state or temper of mind. [Obs.]
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            How cheer'st thou, Jessica?           --Shak.
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   3. To utter a shout or shouts of applause, triumph, etc.
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            And even the ranks of Tusculum
            Could scare forbear to cheer.         --Macaulay.
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WordNet (r) 3.0 (2006):

cheer
    n 1: a cry or shout of approval
    2: the quality of being cheerful and dispelling gloom; "flowers
       added a note of cheerfulness to the drab room" [syn:
       cheerfulness, cheer, sunniness, sunshine] [ant:
       uncheerfulness]
    v 1: give encouragement to [syn: cheer, hearten, recreate,
         embolden] [ant: dishearten, put off]
    2: show approval or good wishes by shouting; "everybody cheered
       the birthday boy"
    3: cause (somebody) to feel happier or more cheerful; "She tried
       to cheer up the disappointed child when he failed to win the
       spelling bee" [syn: cheer, cheer up, jolly along,
       jolly up]
    4: become cheerful [syn: cheer, cheer up, chirk up] [ant:
       complain, kick, kvetch, plain, quetch, sound off]
    5: spur on or encourage especially by cheers and shouts; "The
       crowd cheered the demonstrating strikers" [syn: cheer,
       root on, inspire, urge, barrack, urge on, exhort,
       pep up]