The term "rocksolid" is often used to describe something that is stable, dependable, and unshakable. However, there are many synonyms that can convey a similar meaning and add variety to your writing. Some options include "steadfast," "firm," "stable," "reliable," "solid," "unwavering," "strong," "resolute," "consistent," "unyielding," "unshakeable," and "immutable." Each of these words emphasizes the sense of strength and stability conveyed by "rocksolid," and can be used in different contexts to communicate the same concept. Choosing different synonyms can also add depth and nuance to your writing, making it more interesting and engaging for readers.