dress up
Wear formal or elaborate clothes, as in I love to dress up for a party. [Late 1600s] For the antonym, see dress down, def. 2.
Put on a costume of some kind, as in The children love dressing up as witches and goblins. [Late 1800s]
Adorn or disguise something in order to make it more interesting or appealing. For example, She has a way of dressing up her account with fanciful details. [Late 1600s]