‘masquerade’, as a noun = a costume party (fancy dress party) in which participants wear face masks or strange-looking heavy make-up in order not to be identified), and ‘masquerade’ is also used as a verb = ‘to pretend to be someone else or to disguise in order to cheat someone else’, e.g. ‘The thief masqueraded as a waiter and made away with the guests’ valuables while the party was in full swing.’ (i.e. the thief wore a waiter’s uniform and served the guests for some time and when everybody was enjoying the party, he stole the valuables of the guests and went away)