Attacking someone on a pvp server is never griefing.
If I'm being inconvenienced it's griefing.
If it's unequal levels it's griefing.
If the gear is really unequal it's griefing.
If I have mobs on me it's griefing.
If I have mobs on me and I'm at low health and my cooldowns aren't up it's griefing.
If I'm just trying to quest and this idiot won't leave me alone it's griefing.
If he's camping my corpse it's griefing.
If they're camping our corpses and the GY then it's griefing.
If I'm attacked in a city when I'm just trying to get stuff done it's griefing.