Egoism (noun)

1. The belief that one's own interests or desires are the most important.
2. The habit or practice of being excessively self-centered or self-absorbed.
3. The ethical theory that moral actions are those that serve the agent's own interests.

Origin:

From the latin word "ego" meaning "i" and the suffix "-ism" indicating a state of mind or belief. it entered the english language in the 19th century.

Examples:

1. He was accused of egoism because of his desire to be the center of attention.
2. Her egoism made it difficult for her to work well with others.
3. Many criticized the politician's egoism as he only pursued policies that benefited him and his supporters.
4. Egoism is often seen as a negative trait in a person.
5. He defended his actions as egoism, arguing that he was looking out for his own interests.