the entire wikipedia page is very descriptive, and thought I'd post this short summary:
Signs and Symptoms:
People with narcissistic personality disorder (NPD) are characterized by persistent grandiosity, excessive need for admiration, and a personal disdain and lack of empathy for others.[6][7] As such, the person with NPD usually displays arrogance and a distorted sense of superiority, and they seek to establish abusive power and control over others.[8] Self-confidence (a strong sense of self) is different from narcissistic personality disorder; people with NPD typically value themselves over others to the extent that they openly disregard the feelings and wishes of others, and expect to be treated as superior, regardless of their actual status or achievements.[6][9] Moreover, the person with narcissistic personality disorder usually exhibits a fragile ego (self-concept), intolerance of criticism, and a tendency to belittle others in order to validate their own superiority.[9]
Signs and Symptoms:
People with narcissistic personality disorder (NPD) are characterized by persistent grandiosity, excessive need for admiration, and a personal disdain and lack of empathy for others.[6][7] As such, the person with NPD usually displays arrogance and a distorted sense of superiority, and they seek to establish abusive power and control over others.[8] Self-confidence (a strong sense of self) is different from narcissistic personality disorder; people with NPD typically value themselves over others to the extent that they openly disregard the feelings and wishes of others, and expect to be treated as superior, regardless of their actual status or achievements.[6][9] Moreover, the person with narcissistic personality disorder usually exhibits a fragile ego (self-concept), intolerance of criticism, and a tendency to belittle others in order to validate their own superiority.[9]