Reaction, so no - but only once a turn.
As far as I can tell, you get one reaction per round, but it does not consume your action.There's a disagreement in my group so I thought I'd ask the boards.
Does the "Defender" ability of the cleric of Moradin use up his action on his next turn?
Drop back in and let us know how it went!Great, thanks guys!
Reaction, so no - but only once a turn.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.