overconfident

over- +‎ confident

• IPA^(key): /ˌəʊvə(ɹ)ˈkɒnfɪdənt/

overconfident (comparative more overconfident, superlative most overconfident)

1. Too confident.
   • 2020 April 9, Gaby Hinsliff, “We used to moan about normal life, now our fear is we'll never get it back”, in The Guardian‎:

     The downturn triggered by putting everyday life on hold to halt the infection should, we were told, be V-shaped: a shock, but one from which we’d soon bounce back. Like many comforting predictions in the early days of this pandemic, that is beginning to look alarmingly over-confident.

2. Presumptuous, cocksure, rude and disrespectful.

• insolent, conceited, foolhardy, cocky