The Collaborative International Dictionary of English v.0.48:

Parvenu \Par"ve*nu`\, n. [F., prop. p. p. of parvenir to attain
   to, to succeed, to rise to high station, L. pervenire to come
   to; per through + venire to come. See Par, prep., and
   Come.]
   An upstart; a man newly risen into notice.
   [1913 Webster] Parvis

WordNet (r) 3.0 (2006):

parvenu
    adj 1: characteristic of someone who has risen economically or
           socially but lacks the social skills appropriate for this
           new position [syn: nouveau-riche, parvenu,
           parvenue, upstart(a)]
    2: of or characteristic of a parvenu [syn: parvenu,
       parvenue]
    n 1: a person who has suddenly risen to a higher economic status
         but has not gained social acceptance of others in that
         class [syn: upstart, parvenu, nouveau-riche,
         arriviste]

Moby Thesaurus II by Grady Ward, 1.0:

98 Moby Thesaurus words for "parvenu":
   Babbitt, Daddy Warbucks, Philistine, Young Turk, adventurer,
   arriviste, billionaire, bloated plutocrat, boor, bounder,
   bourgeois, bourgeois gentilhomme, bright young man, cad,
   capitalist, churl, clown, comer, emigrant, epicier, fat cat,
   fledgling, gate-crasher, greenhorn, groundling, guttersnipe,
   hooligan, ill-bred fellow, immigrant, intruder, intrusive, looby,
   lout, low fellow, man of means, man of substance, man of wealth,
   millionaire, modern, modern generation, modern man, modernist,
   modernizer, moneybags, moneyed man, mucker, multimillionaire,
   mushroom, nabob, name-dropper, neologism, neologist, neology,
   neonate, neoteric, neoterism, neoterist, new arrival, new boy,
   new generation, new man, newcomer, newly-rich, nouveau riche,
   nouveau roturier, nouveau-riche, novus homo, parvenue, peasant,
   pig in clover, plutocrat, recruit, ribald, rich man, richling,
   rising generation, rookie, roturier, rough, roughneck, rowdy,
   ruffian, settler, social climber, sprout, squatter, status seeker,
   stowaway, stripling, tenderfoot, tufthunter, upstart, vulgarian,
   vulgarist, warm man, wealthy man, would-be gentleman, yokel