masquerade
US /ˌmæs.kəˈreɪd/
UK /ˌmæs.kəˈreɪd/

1.
a ball or party at which masks and fancy costumes are worn
:
•
The annual charity masquerade ball was held at the old mansion.
•
She wore an elaborate costume to the masquerade.
1.
to pretend to be someone or something that one is not
:
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He tried to masquerade as a wealthy businessman.
•
The spy managed to masquerade as a local villager for months.