1500-1600upstart ‘to jump up suddenly’(14-19 centuries)
Examples
EXAMPLES FROM THE CORPUS
She certainly hoped Albert didn't let in any little upstarts like the officer who'd wanted her apartment!
These upstarts are beating us at our own game, manufacturing and marketing.
We made suggestions, to be overruled by upstarts.
Well, she wasn't about to let this little upstart have her home.
someone who behaves as if they were more important than they really are and who shows a lack of respect towards people who are more experienced or older: a cheeky young upstart—upstart adjective