Festive attire is the name of a dress code that is similar to cocktail attire. T-shirts and denims are a no-go as Christmas outfits, as are casual sweatshirts, boho styles rather suited for the beach and frumpy ensembles. Also called 'holiday attire', this dress code welcomes sequins, tartan, cashmere, velvet, satin, tweed, pearls, fine jewelry and other similar elements.