Action — Riftbound keyword reference

Action is a Riftbound keyword that gives a card or ability permission to be played or activated during a Showdown — a state that normally only lets the active player respond — even when it isn't your turn. It's pure permission: an Action card still follows every other rule for playing it (a unit still needs a base or a battlefield you control), it just isn't locked out of Showdowns the way an ordinary card is.