A griefer or bad faith player is a player in a multiplayer video game who deliberately irritates and harasses other players within the game, by using aspects of the game in unintended ways, such as destroying something another player made or built.

What does it mean to grief someone?

DEFINITIONS1. to annoy someone, or to cause them problems. Synonyms and related words. To make someone angry or annoyed.

What is griefing in real life?

'Griefing' is a term used to describe when a player within a multiplayer online environment intentionally disrupts another player's game experience for his or her own personal enjoyment or gain.