"Go down swinging" refers to someone who never gives up and fights until the very end. Some synonyms for this phrase include "fight tooth and nail," "give it your all," "leave it all on the field." Another synonym could be "perseverance," which means to persist in spite of obstacles. Additionally, "grit" and "resilience" are good synonyms, as they encompass the determination needed to continue fighting. "Tenacity" is another great synonym, referring to the ability to maintain one's tenacity and intensity throughout a difficult situation. In short, there are many great synonyms for "go down swinging" that encapsulate the spirit of tenacity and perseverance.