masquerade

Short definition from Wiktionary

Noun

1. 1
   An assembly or party of people wearing (usually elaborate or fanciful) masks and costumes, and amusing themselves with dancing, conversation, or other diversions.
2. 2
   The act of wearing a mask or dressing up in a costume for, or as if for, a masquerade ball.
3. 3
   An act of living under false pretenses; a concealment of something by a false or unreal show; a disguise, a pretence; also, a pretentious display.
4. 4
   An assembly of varied, often fanciful, things.
5. 5
   A cosplay event at which costumed attendees perform skits.
6. 6
   A dramatic performance by actors in masks; a mask or masque.
7. 7
   A Spanish entertainment or military exercise in which squadrons of horses charge at each other, the riders fighting with bucklers and canes.

Verb

1. 1
   To take part in a masquerade; to assemble in masks and costumes; (loosely) to wear a disguise.
2. 2
   To pass off as a different person or a person with qualities that one does not possess; also, to make a pretentious show of being what one is not.
3. 3
   To conceal (someone) with, or as if with, a mask; to disguise.