The Collaborative International Dictionary of English v.0.48:

Sot \Sot\, n. [F., fr. LL. sottus; of unknown origin, cf. Ir.
   sotal pride, soithir proud, or Chald. & NHeb. shoten
   foolish.]
   1. A stupid person; a blockhead; a dull fellow; a dolt.
      [Obs.] --outh.
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            In Egypt oft has seen the sot bow down,
            And reverence some d?ified baboon.    --Oldham.
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   2. A person stupefied by excessive drinking; an habitual
      drunkard. "A brutal sot." --Granville.
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            Every sign
            That calls the staring sots to nasty wine.
                                                  --Roscommon.
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The Collaborative International Dictionary of English v.0.48:

Sot \Sot\, a.
   Sottish; foolish; stupid; dull. [Obs.] "Rich, but sot."
   --Marston.
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The Collaborative International Dictionary of English v.0.48:

Sot \Sot\, v. t.
   To stupefy; to infatuate; to besot. [R.]
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         I hate to see a brave, bold fellow sotted. --Dryden.
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The Collaborative International Dictionary of English v.0.48:

Sot \Sot\, v. i.
   To tipple to stupidity. [R.] --Goldsmith.
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WordNet (r) 3.0 (2006):

sot
    n 1: a chronic drinker [syn: drunkard, drunk, rummy,
         sot, inebriate, wino]