Narcissism (noun)

1. Excessive self-love or self-centeredness.
2. An inordinate fascination with oneself; excessive self-love; vanity.

Origin:

Late 19th century: from greek narcissismos, from narcissos "narcissus", from the name of the youth narcissus in greek mythology, who fell in love with his own reflection.

Examples:

1. He was accused of having a case of extreme narcissism, as he only talked about himself and his accomplishments.
2. She was suffering from a Narcissistic Personality Disorder, characterized by a long-term pattern of exaggerated feelings of self-importance.
3. The politician's speeches were full of narcissism, always talking about himself in glowing terms.
4. The young celebrity's tweets were full of selfies and narcissism.
5. The book explores the darker side of narcissism, its negative effects on relationships, and how to recognize and deal with it.