up·start 
/ˈʌpˌstɑɚt/ noun
plural up·starts /ˈʌpˌstɑɚt/ noun [count] 1 disapproving : a person who has recently begun an activity, become successful, etc., and who does not show proper respect for older and more experienced people
▪ a young upstart from Harvard who thinks he knows more than the boss 2 chiefly US : a newly successful person, business, etc. — often used before another noun ▪ upstart Internet companies
▪ a young upstart from Harvard who thinks he knows more than the boss
