Dress up Definition 1 of 4Pro Tip 1/3Special Occasions The phrase often implies dressing more elegantly than usual for events like dinners or ceremonies. He dressed up for the awards night. Pro Tip 2/3Visual Appeal Used when someone wants to look particularly attractive, often going beyond their normal style. She really dressed up for the date. Pro Tip 3/3Not Daily Wear Refers to clothes that are not worn every day, setting the outfit apart from the usual attire. I dressed up in a tuxedo for the gala.