What is the meaning of upstart?

noun

• An arrogant or presumptuous person.
• A person who has suddenly risen to a higher economic status but has not gained social acceptance of others in that class.
  • synonyms: parvenu, nouveau-riche, arriviste
• A gymnastic exercise performed starting from a position with the legs over the upper body and moving to an erect position by arching the back and swinging the legs out and down while forcing the chest upright.
  • synonyms: kip

adjective

• Characteristic of someone who has risen economically or socially but lacks the social skills appropriate for this new position.
  • synonyms: nouveau-riche, parvenu, parvenue