As nouns the difference between grandiosity and narcissism
is that grandiosity is the state of being grandiose (pompous or pretentious) while narcissism is excessive love of oneself.
grandiosity
English
Noun
The state of being grandiose (pompous or pretentious).
narcissism
English
(narcissism)
Noun
(en-noun)
Excessive love of oneself.
Sexual desire for one's own body.
Derived terms
* narcissist
* narcissistic
*narcissize