The word "transmutable" refers to the ability to change or transform into something else. Synonyms that could be used to describe something that is even more transmutable could include words such as malleable, adaptable, pliable, flexible, or mutable. These words all suggest a high degree of fluidity or changeability in something, indicating a potential for transformation or modification. This could be applied to a variety of contexts, such as describing a person's mindset or an object's physical properties. Ultimately, any word used to describe something as "more transmutable" points to a quality of flexibility and transformation, suggesting potential for growth and change.