WordNet (r) 3.0 (2006):

arriviste
    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:

64 Moby Thesaurus words for "arriviste":
   Babbitt, Philistine, Young Turk, boor, bounder, bourgeois,
   bright young man, cad, churl, clown, comer, emigrant, epicier,
   fledgling, gate-crasher, greenhorn, groundling, guttersnipe,
   hooligan, ill-bred fellow, immigrant, intruder, looby, lout,
   low fellow, modern, modern generation, modern man, modernist,
   modernizer, mucker, neologism, neologist, neology, neonate,
   neoteric, neoterism, neoterist, new arrival, new boy,
   new generation, new man, newcomer, nouveau riche, novus homo,
   parvenu, peasant, recruit, ribald, rising generation, rookie,
   rough, roughneck, rowdy, ruffian, settler, squatter, stowaway,
   stripling, tenderfoot, upstart, vulgarian, vulgarist, yokel