megalomania has definitions from the fields of psychology,psychiatry
[ noun ] (psychology,psychiatry) a psychological state characterized by delusions of grandeur

Used in print

(Harold Rosenberg, "The Trial and Eichmann"...)

fearful of being mistaken for a Jew , he seeks protection in his Nazi uniform ; clinging to the enemy Jew idea , he is forced to overcome habits of politeness and neighborliness ; once in power he begins to give_vent to a criminal opportunism that causes him to alternate between megalomania and envy of those above him .