The phrase "ultra-ultra" is used to describe something extremely or excessively extreme. Some synonyms for this phrase include: hyper, super, extreme, radical, intensified, intensified, excessive, and ultimate. These words can be used interchangeably to convey the same meaning as "ultra-ultra". For instance, one might describe a person who is extremely passionate about a cause as "hyper-passionate" or "super-passionate". Similarly, one might describe a situation that is excessively intense as "radical" or "extreme". Overall, the synonyms for "ultra-ultra" help convey a sense of intensity or extremity in a way that is more creative and nuanced than the original phrase.