If it makes you feel any better, I had a tank ask me what "Active Mitigation" was yesterday... In Vault of the Wardens Mythic. The day before on Arcway Mythic, I was told to stop dps'ing and heal. I will give you one guess as to what class these two were playing, and one guess as to what (healer) spec I play, haha.
The glory of start of expac dungeons. I do love the challenges, I just hate the players.