noun

• (countable) A cause or instance of sorrow or pain; that which afflicts or distresses; a trial.
  "Surely, he hath borne our griefs, and carried our sorrows."

verb

• (online gaming) To deliberately harass and annoy or cause grief to other players of a game in order to interfere with their enjoyment of it; especially, to do this as one’s primary activity in the game, and especially by exploiting game mechanics without using cheats to do so, often through acts of destruction or vandalism.
  "While ban and his pals stand squarely in this tradition, they also stand for something new: the rise of organized griefing, grounded in online message-board communities and thick with in-jokes, code words, taboos, and an increasingly articulate sense of purpose. No longer just an isolated pathology, griefing has developed a full-fledged culture."