deck out
1. 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.
2. To decorate something lavishly or elaborately. A noun or pronoun can be used between "deck" and "out." Wow, you really decked out the house for the party tonight—I've never seen so many Christmas lights in my life!
deck someone or something out (in something)
and deck someone or something out (with something)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. Tom decked the room out with garlands of flowers.
deck out
Decorate, dress up, as in They were all decked out in their best clothes. [Mid-1700s]