nouveau riche(new money: wealthy persons whose fortunes are newly acquired, and who are therefore perceived to lack the refinement of those who were raised wealthy) noun [UK: ˈnuː.vəʊ.ˈriːʃ] [US: ˈnuː.vəʊ.ˈriːʃ]
upstart [upstarts](newly rich or prominent) noun [UK: ˈʌp.stɑːt] [US: ˈʌp.ˌstɑːrt]