1. adjective
Overbearingly arrogant; ostentatiously self-important or self-aggrandizing.
Ever since she was placed in the gifted program, shes become so high and mighty that no one wants to be near her.
2. noun
A social or economic group wielding undue power, influence or economic clout.
The high and mighty are to be found at the Fairlawn Country Club on pleasant afternoons.
Wikipedia foundation.