Antonyms, or words with opposite meanings, of "most trendsetting" can include traditional, outdated, behind-the-times, unpopular, and unfashionable. These words suggest a lack of innovation, originality, and style, and may connote a sense of conservatism or resistance to change. They are often used to describe things that are old-fashioned or no longer relevant to current trends, and may be perceived as boring or out of touch. While there may be situations where traditional or classic styles are preferred, in many contexts, being "most trendsetting" is seen as desirable and indicative of being ahead of the curve.