The Collaborative International Dictionary of English v.0.48:

Linguist \Lin"guist\ (l[i^][ng]"gw[i^]st), n. [L. lingua tongue,
   speech, language: cf. F. linguiste.]
   1. A master of the use of language; a talker. [Obs.]
      [1913 Webster]

            I'll dispute with him;
            He's a rare linguist.                 --J. Webster.
      [1913 Webster]

   2. A person skilled in languages.
      [1913 Webster]

            There too were Gibbon, the greatest historian, and
            Jones, the greatest linguist, of the age.
                                                  --Macaulay.
      [1913 Webster] Linguistic

WordNet (r) 3.0 (2006):

linguist
    n 1: a specialist in linguistics [syn: linguist, linguistic
         scientist]
    2: a person who speaks more than one language [syn: linguist,
       polyglot]

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "linguist":
   bilingual, dialectician, diglot, etymologer, etymologist,
   glossarist, glossographer, grammarian, grammaticaster, grammatist,
   lexicographer, lexicologist, linguistic scholar,
   linguistic scientist, linguistician, multilingual, orthoepist,
   paleographer, philologaster, philologer, philologian, philologist,
   phonemicist, phonetician, phoneticist, phonologist, polyglot,
   semanticist, semasiologist