1) Egocentric 2) Egoist 3) Egotist 4) Power-crazed person 5) Swellhead 
A person exhibiting megalomania. ... (05 Mar 2000) ... 
Type: Term Pronunciation: meg′ă-lō-mā′nē-ak Definitions: 1. A person exhibiting megalomania.
[n] - a pathological egotist
megalomania, megalomaniac 1. An unreasonable delusionary conviction of one’s own extreme greatness, goodness, or power; the ideas in megalomania are known as delusions of grandeur and are generally considered a part of schizophrenia or other psychoses. 2. Loosely, the term is also used to describe a lopsided attachment or passion for, or for d...
noun a pathological egotist