A narcissist is a person who is extremely self-centered [thinking mainly about oneself and not considering others] and has an excessive admiration for themselves. They often lack empathy for others [understanding and sharing the feelings of others] and have a constant need for attention and validation.
For example, a narcissist may constantly talk about their achievements and seek praise and compliments from others. They may also disregard the feelings and needs of others in order to fulfill their own desires.
Very Simple Definition:
A narcissist is someone who is obsessed with themselves and doesn’t care about other people’s feelings. They always want attention and think they are better than everyone else.
For example, a narcissist might always talk about how great they are and ignore what other people want. They only care about themselves.