The word "supercow" can be used to describe a cow that is exceptional in some way, but there are several other words that can be used as synonyms. "Hero cow" or "heroine cow" can be used to describe a cow that has saved a human or animal from danger, while "champion cow" or "winner cow" can be used to describe a cow that has won a competition or award. Other synonyms for "supercow" include "superior cow," "elite cow," and "top-notch cow." Regardless of the synonym used, each word indicates that the cow is exceptional and stands out from the rest of the herd.