This is called semantic drift.

Word becomes misused too often, then overused so much that it loses its original meaning.

Griefing originally meant something obviously malicius towards your own team in gaming, as in destroying allied buildings, blocking allied paths, killing allies players with the intention to make them suffer and lose.

Then it became the FOMO buzzword and all of a sudden doing something game losing (like, accidentally pressing a BKB while farming) all of a sudden became «griefing», and now nobody even know what griefing is.

Yes, I suck at the game. I constantly do stupid stuff like dying out of position and saving enemies by using spells that can make it hard for my teammates to kill enemies (something like clock's cogs).

I never grief my team, I'm just bad at the game.