A person who has recently arrived at wealth, status, or social position; a social climber or upstart.
From French 'arriviste,' formed from 'arriver' (to arrive) plus '-iste.' It entered English in the 19th century as a borrowing from French society criticism.
Old money used 'arriviste' as an insult against new money—it suggested you'd only just 'arrived' (implying you didn't belong naturally there), and the word perfectly captures how societies have always looked down on people who rise too quickly.
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