Solid body refers to an object that is three-dimensional and has definite shape and volume. There are several synonyms for this term that can be used interchangeably. Some of the most commonly used include firm, stable, compact, and rigid. Other synonyms that may fit depending on context include robust, substantial, concrete, and tangible. Each of these synonyms highlights aspects of a solid body, such as strength, durability, or material properties. When choosing synonyms, it's important to consider the intended meaning and tone of the message being conveyed to ensure that readers can understand the intended meaning clearly.