Parvenu (7)
I believe the answer is:
upstart
'parvenu' is the definition.
(I know that parvenu can be written as upstart)
This is all the clue.
(Other definitions for upstart that I've seen before include "Person who has suddenly risen in wealth or importance" , "Arrogant newcomer" , "One who suddenly rises from nowhere to importance" , "Person who behaves arrogantly in the new position" , "Person suddenly risen in world, and arrogant" .)