The hallmarks of narcissistic personality disorder (NPD) are grandiosity, a lack of empathy for other people, and a need for admiration. People with this condition are frequently described as arrogant, self-centered, manipulative, and demanding. They may also have grandiose fantasies and may be convinced that they deserve special treatment. These characteristics typically begin in early adulthood and must be consistently evident in multiple contexts, such as at work and in relationships.
People with NPD often try to associate with other people they believe are unique or gifted in some way, which can enhance their own self-esteem. They tend to seek excessive admiration and attention and have difficulty tolerating criticism or defeat.
Although NPD is a difficult disorder to treat, therapy can help those with the condition develop their sense of self and their relationships.
NPD refers to the diagnosable mental disorder, while the term "narcissism" is a trait that ranges in degree from person to person.
Sourced from: https://www.psychologytoday.com/us?tr=Hdr_Brand