megalomaniaPronunciation: /ˌmɛg(ə)lə(ʊ)ˈmeɪnɪə/Translate megalomania | into German | into Italian Definition of megalomania noun [mass noun] obsession with the exercise of power. delusion about one’s own power or importance (typically as a symptom of manic or paranoid disorder). Derivatives megalomanicPronunciation: /-ˈmanɪk/ adjective megalomania in other Oxford dictionaries Definition of megalomania in the US English dictionary