When you need to describe something as "more rocksolid," it means you want to emphasize its strength, reliability, and stability. There are several synonyms for this phrase that can help you convey its meaning more precisely. For instance, you can describe something as "more unshakeable," "more indestructible," or "more unwavering" to highlight its unbreakable nature. Similarly, you can use words like "more steadfast," "more dependable," and "more secure" to emphasize its trustworthy and reliable character. Other synonyms for "more rocksolid" include "more immovable," "more resolute," and "more firm," each of which carries the connotation of a solid, unyielding foundation.