Self-interest can be defined as the pursuit of one's own individual benefit or gain. There are several synonyms for this term that can be used in different contexts. Some of the common synonyms for self-interest include personal gain, individualism, egoism, self-satisfaction, self-serving, self-centeredness, self-gratification, self-advancement, self-preservation, and self-absorption. However, it is important to note that self-interest can have a negative connotation in some cases, especially if it involves taking advantage of others or disregarding their needs. Therefore, it is essential to use such terms with caution and sensitivity depending on the context and tone of the conversation.