upstart: [16] An upstart is etymologically simply someone who has ‘started up’ – but start in its early sense ‘jump, spring, rise’. Start-up was an early alternative version of the word (‘That young start-up hath all the glory of my overthrow’, says Don John in Shakespeare’s Much Ado About Nothing 1599), but it did not survive the 17th century.
1550s, "one newly risen from a humble position to one of power, importance, or rank, a parvenu," also start-up, from up (adv.) + start (v.) in the sense of "jump, spring, rise." As an adjective from 1560s. Compare the archaic verb upstart "to spring to one's feet," attested from c. 1300.
