1. noun /ɡriːf/
a) Suffering, hardship.
She was worn out from so much grief.
b) Pain of mind arising from misfortune, significant personal loss, misconduct of oneself or others, etc.; sorrow; sadness.
The betrayal caused Jeff grief.
2. verb /ɡriːf/
To deliberately harass and annoy 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.
Wikipedia foundation.