fancy dress
US /ˌfæn.si ˈdres/
UK /ˌfæn.si ˈdres/

1.
travestimento, costume
clothes worn for a party where everyone dresses as a particular type of character or thing
:
•
She wore a fairy costume to the fancy dress party.
Ha indossato un costume da fata alla festa in maschera.
•
The theme of the party is fancy dress from the 80s.
Il tema della festa è il travestimento degli anni '80.