egomaniacnoun [ C ]
uk/ˌiː.ɡəʊˈmeɪ.ni.æk//-ɡoʊ-/disapprovingsomeone who considers themselvesto be very important and able to do anything that they want:
Some celebs are just self-absorbed egomaniacs.
egomaniacal
adjective uk/ˌiː.ɡəʊ.məˈnaɪə.kəl//-ɡoʊ-/disapproving
The office is filled with brilliant egomaniacal workaholics.