Late 17th century; earliest use found in George Havers (fl. 1665). From classical Latin Nerōn-, Nerō + -ism, after Italian Neronismo. Compare French néronisme.
Definition of Neronism in US English:
Neronism
nounˈnɪərənɪz(ə)m
rare
Neronian style, character, or behaviour.
Origin
Late 17th century; earliest use found in George Havers (fl. 1665). From classical Latin Nerōn-, Nerō + -ism, after Italian Neronismo. Compare French néronisme.