masquerade

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A costume party at which masks are worn; a masked ball.
• noun A costume for such a party or ball.
• noun A disguise or false outward show; a pretense.
• noun An involved scheme; a charade.
• intransitive verb To wear a mask or disguise, as at a masquerade.
• intransitive verb To go about as if in disguise; have or put on a deceptive appearance.

from The Century Dictionary.

• To wear a mask; take part in a masquerade.
• To disguise one's self.
• To cover with a mask or disguise.
• noun An assembly of persons wearing masks and usually other disguises, or rich and fantastic dress: usually, a dancing-party or ball. See mask-ball.
• noun Disguise effected by wearing a mask or strange apparel; hence, concealment or apparent change of identity by any means; disguise in general.
• noun The costume of a person who joins in a masquerade; disguising costume of any sort.
• noun A Spanish diversion on horseback. See the quotation.
• noun A changeable or shot silk.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To conceal with masks; to disguise.
• intransitive verb To assemble in masks; to take part in a masquerade.
• intransitive verb To frolic or disport in disquise; to make a pretentious show of being what one is not.
• noun An assembly of persons wearing masks, and amusing themselves with dancing, conversation, or other diversions.
• noun obsolete A dramatic performance by actors in masks; a mask. See 1st Mask, 4.
• noun Acting or living under false pretenses; concealment of something by a false or unreal show; pretentious show; disguise.
• noun A Spanish diversion on horseback.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A party or assembly of people wearing masks, and amusing themselves with dancing, conversation, or other diversions.
• noun obsolete A dramatic performance by actors in masks; a mask. See “mask”
• noun Acting or living under false pretenses; concealment of something by a false or unreal show; pretentious show; disguise.
• noun A Spanish diversion on horseback.
• verb intransitive To assemble in masks; to take part in a masquerade.
• verb intransitive To frolic or disport in disguise; to make a pretentious show of being what one is not.
• verb transitive To conceal with masks; to disguise.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb take part in a masquerade
• noun making a false outward show
• noun a party of guests wearing costumes and masks
• verb pretend to be someone or something that you are not
• noun a costume worn as a disguise at a masquerade party