parvenu
noun
a person who has recently or suddenly acquired wealth, importance, position, or the like, but has not yet developed the conventionally appropriate manners, dress, surroundings, etc.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
I did not want to show any sensational parvenuism; London is not impressed by that.
From The Secrets of the German War Office by Dr. Armgaard Karl Graves