Wait is a unique action skill available to all playable characters in MARDEK. Wait can be used by a playable character in battle by navigating to the appropriate button, by pressing Z (if 'Z to Wait' is enabled), or by pressing Y (if both 'Z to Wait' and 'QWERTZ compatibility' are enabled). It cannot be used outside of battle.
Wait ends the active playable character's turn without taking action.
If the active playable character is Elwyen, and she is playing one of her Siren Songs, the default position of her menu will change from Attack to Wait. Using Wait in these circumstances will cause Elwyen to continue playing the same song. She will not gain any AP from this, however.