jumped-up 
adjective informal
Denoting someone who considers themselves to be more important than they really are, or who has suddenly and undeservedly risen in status: she’s not really a journalist, more a jumped-up PR woman...
- And we thought they were all just jumped-up waitresses.
- And if that's what they want, they should never change just for the sake of being able to spend a bit of time with some jumped-up idiot.
- He was a jumped-up Austrian, a loner, always excluded from picnics and parties, and to compensate he always felt he had to be on top of his game.