Live Action Role Play. A LARPer is someone pretending to be something they're really not.

In the 70's and 80's LARPs were people dressing up like dungeons and dragons for Renaissance Fair. Since the dawn of YouTube and social media, LARPs are the new psyops. People LARP on YouTube as Truthers, Christians, Social Justice Warriors, and civilians.
govLARP = agents of the government pretending to be civilians. Crisis Actors = LARPers.
LARPwars = two or more LARPers in a social media pseudo-feud.

Style with Ease

Legacies Role Play System

LaRPS is a roleplaying system in use for monitoring and advancing a players statistics throughtout their roleplaying session. Its prime use is in Second Life, OpenSim and other virtual worlds where avatars use storytelling as part of interactive scenes, which may include combat, in a virtual community environment.

Live Action Role Play

a type of game where a group of people wear costumes representing a character they create to participate in an agreed fantasy world. Uses foam sticks as swords, foam balls as magic and other props to create the games world.

Live Action Role Playing.
As everyone said, it is mostly used by attention whores. However, it can be used, and often in some parts areas, to shitpost and shill.

A fancy name for playing pretend.

Live Action Role Play (n)
Verb form: To LARP, LARPing, LARPed, etc.

LARPs are a category of game in which players create characters and, acting as those characters, interact with other players and Storytellers/Game Masters to complete some sort of challenge, quest, or adventure. LARPing traditionally has its roots in so-called "table top" games like Dungeons and Dragons or White Wolf's Vampire the Masquerade, however in table top games, the game mechanics are controlled by dice. In LARPing, game mechanics are usually controlled by rock-paper-scissors.

Although some forms of LARPs do include foam weapons (known as "Boffer weapons") and medieval/fantasy costuming, others take place in the real world with current clothes and can be played in public spaces so long as players have an identifying object such as a red button or other signifier to tell other players who is involved in the game. These games generally do not include actual weapons of any sort, foam or otherwise, and players wishing to use a weapon against another character must describe what they are doing and then play rock-paper-scissors to determine if they are successful.

Vampire the Masquerade is one of the more successful LARPs out there, having several groups throughout the United States. Large numbers of LARPers are therefore often walked past by unsuspecting passerby who think they've just seen a bunch of loitering goths. Although they are not wrong, they have also witnessed LARPing.