The opposite of "more rocklike" would be "less rocklike" or "more soft" or "more malleable." Other antonyms for "rocklike" could include "pliable," "flexible," "yielding," "bendable," "elastic," or "supple." These words suggest a lack of hardness or rigidity in an object or substance. Instead of being solid and unyielding, a material that is less rocklike would be easy to shape or deform. Some examples of materials that might be described as less rocklike could include clay, marshmallow, rubber, or foam. Ultimately, the appropriate antonym for "more rocklike" depends on the context in which it is used and the specifics of the comparison being made.