upstart

1. N-COUNT You can refer to someone as an upstart when they behave as if they are important, but you think that they are too new in a place or job to be treated as important. 自命不凡的新手[表不滿]

Many prefer a familiar authority figure to a young upstart. 許多人更喜歡熟悉的權威人物而不喜歡自命不凡的年輕新貴。