An "arbiter of fashion" is someone who is considered an authoritative figure in the fashion industry. This person may be a designer, stylist, editor, or blogger who has gained a reputation for their keen eye and discerning taste. Other words that could be used to describe an arbiter of fashion include "trendsetter," "fashionista," "influencer," or "style icon." These terms suggest that the person in question plays a significant role in shaping the way people dress and think about fashion. Regardless of what they are called, an arbiter of fashion has the power to influence the direction of the industry and set the standards for what is considered stylish and desirable.