What's the noun for parvenuesses? Here's the word you're looking for.
parvenu
A person who has risen, climbed up, or has been promoted to a higher social class, especially through acquisition of wealth, rights, or political authority but has not gained social acceptance by those within that new class.
“It sounds good that some of the parvenus have volunteered to pay taxes.”
“This lingual magniloquence is proverbial of American parvenus.”
“Through this easy gap emerged into life the rich supernumeraries who drove their tilburys, dressed well, and wore moustachios, all of them as impudent as parvenus.”