What is the definition or description of: narcissism?

" I am the greatest": A pervasive sense of grandiosity in fantasy or behavior, lack of empathy, need for admiration, fantasies o unlimited success, sense of entitlement, envious of others, often arrogant, exploitive of others as well as other characteristics. Person would definitely benefit by therapy but often by nature of the condition the person doesn't believe that there is anything wrong with them

Narcissism: The hallmark of a narcissist is an immense ego, grandiosity, and self-importance, as well as being entitled, and a tendency to use and objectify others as well as thinking of people in all-good or all-bad terms instead of shades of gray. The core of a narcissist is profound insecurity.