upstart

/ˈʌpstɑrt/
adjective
  1. Characteristic of an upstart; suddenly risen to prominence and often seen as arrogant or presumptuous.
    • Her upstart attitude annoyed the senior members of the club.
    • The upstart company tried to take over the market with aggressive tactics.
    • He had an upstart confidence that rubbed people the wrong way.
Antonyms
noun
  1. A person who has recently become successful or powerful and behaves arrogantly, often seen as an outsider by more established people.
    • He was called an upstart after he bought the company and changed all the rules.
    • The old executives viewed the young entrepreneur as an upstart who didn't respect tradition.
    • The upstart challenged the veteran politician in the election.
Antonyms
What does "upstart" mean? | whatsthatwordmean | whatsthatwordmean