A costume party at which masks are worn; a masked ball. Also called masque. A costume for such a party or ball. A disguise or false outward show; a pretense: a masquerade of humility. An involved scheme; a charade. To wear a mask or disguise, as at a masquerade: She masqueraded as a shepherd. To go about as if in disguise; have or put on a deceptive appearance: The stowaway masqueraded as a crew member.