WordNet sense 1 (characteristic of someone who has risen economically or socially but lacks the social skills appropriate for this new position):

parvenu, upstart, nouveau-riche

WordNet sense 2 (making claim to or creating an appearance of (often undeserved) importance or distinction):

pretentious

WordNet sense 3 (not of long duration; having just (or relatively recently) come into being or been made or acquired or discovered):

new