A man who is constantly checking out his outfit in the mirror might be foppish, or someone who loves dressing up in fancy clothes.

For some reason, foppish is almost always used to describe men (not women), and that's why the word might make you think of an elegant suit, vest, and tie, and probably some over-the-top details like a flower in a buttonhole and a polka-dotted handkerchief. The word foppish also implies that this guy probably thinks he looks pretty good.

Definitions of foppish

adj affecting extreme elegance in dress and manner

dandified, dandyish
refined and tasteful in appearance or behavior or style