The Collaborative International Dictionary of English v.0.48:

Proletarian \Prol`e*ta"ri*an\, a. [L. proletarius. See
   Proletary.]
   Of or pertaining to the proletaries; belonging to the
   commonalty; hence, mean; vile; vulgar. "Every citizen, if he
   were not a proletarian animal kept at the public cost." --De
   Quincey. -- n. A proletary.
   [1913 Webster]

WordNet (r) 3.0 (2006):

proletarian
    adj 1: belonging to or characteristic of the proletariat
    n 1: a member of the working class (not necessarily employed);
         "workers of the world--unite!" [syn: proletarian,
         prole, worker]