In Short: semi-formal / dressy casual! What does this mean? : Part of dressing for a semi-formal, or dressy casual, wedding is paying close attention to when the ceremony will take place. For evening events, darker, more formal colors are best, whereas light hues and airy fabrics are preferred for daytime affairs. Women can wear below-the-knee dresses, slip dresses, a dressy skirt and top, or an elegant pantsuit (styled with heels, nice wedges, or formal flats). As for men, settle on a dress shirt and slacks, with the option to wear a tie. "Semi-formal gives you flexibility on comfort, but be sure not to dress too casually,