parvenu — a person of obscure origin who has gained wealth, influence, or celebrity

a flashily dressed man with expensive jewelry and designer clothes loudly boasts about his recent business success to uncomfortable aristocrats. He gestures wildly while showing off his gold watch and diamond rings to the refined guests. The old-money members exchange disapproving glances and whisper behind their hands about his crude behavior. Their stiff postures and raised eyebrows contrast sharply with his animated bragging and ostentatious display. Other club members turn away or look down their noses at his obvious attempt to fit into their exclusive social circle. a person of humble origins who has gained wealth and influence but lacks the refined manners of established society