Compulsatory is an adjective that describes something that is required, mandatory, or obligatory. There are several synonyms for the word compulsatory, including compulsory, necessary, indispensable, non-negotiable, essential, imperative, requisite, mandatory, and compulsive. These words all imply a sense of obligation or duty, and they are commonly used in legal, academic, and professional settings. Each of these synonyms expresses a slightly different shade of meaning, but they can all be used interchangeably in most contexts. If you are looking for other words that convey a similar sense of obligation or necessity, consider using phrases like "must-have," "required," or "must-do".