Source : Webster's Revised Unabridged Dictionary (1913)

Sober \Sober\, a. [Compar. {Soberer}; superl. {Soberest}.] [OE.
   sobre, F. sobre, from L. sobrius, probably from a prefix so-
   expressing separation + ebrius drunken. Cf. {Ebriety}.]
   1. Temperate in the use of spirituous liquors; habitually
      temperate; as, a sober man.

            That we may hereafter live a godly, righteous, and
            sober life, to the glory of Thy holy name. --Bk. of
                                                  Com. Prayer.

   2. Not intoxicated or excited by spirituous liquors; as, the
      sot may at times be sober.

   3. Not mad or insane; not wild, visionary, or heated with
      passion; exercising cool, dispassionate reason;
      self-controlled; self-possessed.

            There was not a sober person to be had; all was
            tempestuous and blustering. --Druden.

            No sober man would put himself into danger for the
            applause of escaping without breaking his neck.
                                                  --Dryden.

Sober \So"ber\, v. t. [imp. & p. p. {Sobered}; p. pr. & vb. n.
   {Sobering}.]
   To make sober.

         There shallow draughts intoxicate the brain, And
         drinking largely sobers us again.        --Pope.

Sober \So"ber\, v. i.
   To become sober; -- often with down.

         Vance gradually sobered down.            --Ld. Lytton.

Source : WordNet®

sober
     v 1: cause to become sober; "A sobering thought"
     2: become more realistic; "After thinking about the potential
        consequences of his plan, he sobered up" [syn: {sober up}]
     3: become sober after excessive alcohol consumption; "Keep him
        in bed until he sobers up" [syn: {sober up}]

sober
     adj 1: not affected by a chemical substance (especially alcohol)
            [ant: {intoxicated}]
     2: dignified and somber in manner or character and committed to
        keeping promises; "a grave God-fearing man"; "a quiet
        sedate nature"; "as sober as a judge"; "a solemn promise";
        "the judge was solemn as he pronounced sentence" [syn: {grave},
         {sedate}, {solemn}]
     3: lacking brightness or color; dull; "drab faded curtains";
        "sober Puritan gray"; "children in somber brown clothes"
        [syn: {drab}, {somber}, {sombre}]
     4: completely lacking in playfulness [syn: {unplayful}, {serious}]
        [ant: {playful}]