deck one out

"a streetcar named desire" からの引用です。
Blanche has been drinking fairly steadly since Mitch left. She has dragged her wardrobe trunk into the center of the bedroom. It hangs open with flowery dresses thrown across it. As the drinking and packing went on, a mood of hysterical exhilaration came into her and she has decked herself out in a somewhat soiled and crumpled white satin evening gown and a pair of scuffed silver slippers with brilliants set in their heels.
"decked herself out" の個所を調べます。
・Farlex Dictionary of Idioms: To dress in an especially extravagant manner. A noun or pronoun can be used between "deck" and "out.": Wow, you sure got decked out for the party tonight! Maybe I should have worn something nicer than jeans.

・American Heritage Dictionary: Decorate, dress up, as in They were all decked out in their best clothes.

・McGraw-Hill Dictionary of American Idioms and Phrasal Verbs: to decorate someone or something with something. Sally decked all her children out for the holiday party. She decked out her children in Halloween costumes.