Fop, dandy, beau, coxcomb, exquisite, dude, buck are comparable when denoting a man who is conspicuously fashionable or elegant in dress or manners.
Fop is applied to a man who is preposterously concerned with fashionableness, elegance, and refinement not only in respect to dress and manners but in respect to such matters as literary or artistic taste.
Dandy carries a weaker implication of affectation and overrefinement than fop and a stronger suggestion of concern for stylish or striking apparel and a spruce or dapper appearance.
Beau suggests as much attention to details of personal appearance as does fop.
Coxcomb, like fop, is applicable to a beau as a term of contempt; it often stresses fatuousness and pretentiousness as much as or more than foppishness.
Exquisite is a somewhat old-fashioned designation of a dandy who manifests the extreme delicacy and refinement of taste characteristic of a fop.
Dude applies chiefly to a man who makes himself conspicuously different in dress or manners from the ordinary man; it is therefore the rough man’s term for the carefully dressed and groomed man, the quiet gentleman’s term for the obvious dandy, or a Western American’s term for an Easterner or a city-bred man.
Buck applies usually to a dashing fellow, a dandy in dress, but not conspicuously, or necessarily, a gentleman in manners.