Delusions of grandeur refers to a mental condition where a person thinks that they possess remarkable qualities or abilities that they actually do not have. There are several synonyms for this term, including megalomania, narcissism, and self-importance. Megalomania is a personality disorder characterized by delusions of grandeur, power, and dominance. Narcissism is a condition in which a person has an excessive love for oneself, along with a lack of empathy and an almost pathological need for admiration. Self-importance, on the other hand, refers to a person's feeling of superiority, importance, or self-worth, which may not be grounded in reality. Overall, delusions of grandeur can manifest in different ways, but the core feature remains the same - an exaggerated and unrealistic sense of one's own abilities and importance.