The Collaborative International Dictionary of English v.0.48:

Capitalist \Cap"i*tal*ist\ (k[a^]p"[i^]*tal*[i^]st), n. [Cf. F.
   capitaliste.]
   One who has capital; one who has money for investment, or
   money invested; esp. a person of large property, which is
   employed in business.
   [1913 Webster]

         The expenditure of the capitalist.       --Burke.
   [1913 Webster]

WordNet (r) 3.0 (2006):

capitalist
    adj 1: of or relating to capitalism or capitalists; "a
           capitalist nation"; "capitalistic methods and incentives"
           [syn: capitalist, capitalistic]
    2: favoring or practicing capitalism [syn: capitalistic,
       capitalist] [ant: socialist, socialistic]
    n 1: a conservative advocate of capitalism
    2: a person who invests capital in a business (especially a
       large business)

Moby Thesaurus II by Grady Ward, 1.0:

32 Moby Thesaurus words for "capitalist":
   Daddy Warbucks, Wall Streeter, billionaire, bloated plutocrat,
   bourgeois, economist, fat cat, finance capitalist,
   financial expert, financier, free-enterprise, individualist,
   individualistic, investor, man of means, man of substance,
   man of wealth, millionaire, moneybags, moneyed man, moneyman,
   multimillionaire, nabob, nonsocialistic, parvenu, plutocrat,
   private-enterprise, rich man, richling, rugged individualist,
   warm man, wealthy man