"Un-imagined" means something that has not been thought of or envisioned before. Synonyms of "un-imagined" can be "unforeseen," "unexpected," "unprecedented," "unanticipated," "unpredicted," "surprising," "amazing," "astounding," "stupefying," "incredible," "unbelievable," and "mind-blowing." These words tend to highlight the suddenness or the shock factor of something that was not expected or initially conceived. These synonyms can be used in varied contexts, ranging from describing a new scientific discovery, an unprecedented societal change, or a breathtaking natural phenomenon. Overall, "un-imagined" and its synonyms convey the idea of things that were not considered or predicted before, adding excitement and novelty to our understanding of the world.