overconfident

adj

1. Too confident.

   “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.”

   “By propagating a "reality distortion field"—that is, mesmerizing potential employees, investors, and strategic partners so they focus on a startup's world-changing potential rather than on its real-world risks—overconfident and charismatic founders in particular are able to persuade people to commit resources under terms favorable to their new venture.”

2. (also, sometimes)Too confident.

   “Near-synonyms: insolent, conceited, foolhardy, cocky”