The Collaborative International Dictionary of English v.0.48:

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.
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            That we may hereafter live a godly, righteous, and
            sober life, to the glory of Thy holy name. --Bk. of
                                                  Com. Prayer.
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   2. Not intoxicated or excited by spirituous liquors; as, the
      sot may at times be sober.
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   3. Not mad or insane; not wild, visionary, or heated with
      passion; exercising cool, dispassionate reason;
      self-controlled; self-possessed.
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            There was not a sober person to be had; all was
            tempestuous and blustering. --Druden.
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            No sober man would put himself into danger for the
            applause of escaping without breaking his neck.
                                                  --Dryden.
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   4. Not proceeding from, or attended with, passion; calm; as,
      sober judgment; a man in his sober senses.
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   5. Serious or subdued in demeanor, habit, appearance, or
      color; solemn; grave; sedate.
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            What parts gay France from sober Spain? --Prior.
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            See her sober over a sampler, or gay over a jointed
            baby.                                 --Pope.
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            Twilight gray
            Had in her sober livery all things clad. --Milton.
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   Syn: Grave; temperate; abstinent; abstemious; moderate;
        regular; steady; calm; quiet; cool; collected;
        dispassionate; unimpassioned; sedate; staid; serious;
        solemn; somber. See Grave.
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