Source : Webster's Revised Unabridged Dictionary (1913)

Slav \Slav\, n.;pl. {Slavs}. [A word originally meaning,
   intelligible, and used to contrast the people so called with
   foreigners who spoke languages unintelligible to the Slavs;
   akin to OSlav. slovo a word, slava fame, Skr. [,c]ru to hear.
   Cf. {Loud}.] (Ethnol.)
   One of a race of people occupying a large part of Eastern and
   Northern Europe, including the Russians, Bulgarians,
   Roumanians, Servo-Croats, Slovenes, Poles, Czechs, Wends or
   Sorbs, Slovaks, etc. [Written also {Slave}, and {Sclav}.]

Source : WordNet®

Slav
     adj : speaking a Slavic language; "the Slav population of Georgia"

Slav
     n : any member of the people of eastern Europe or Asian Russia
         who speak a Slavonic language