In Dungeon World, the Cleric class has the following starting move:
Turn Undead
When you hold your holy symbol aloft and call on your deity for protection, roll+Wis. ✴On a 7+, so long as you continue to pray and brandish your holy symbol, no undead may come within reach of you. ✴On a 10+, you also momentarily daze intelligent undead and cause mindless undead to flee. Aggression breaks the effects and they are able to act as normal. Intelligent undead may still find ways to harry you from afar. They’re clever like that.
The stated actions involved are "praying" and "brandishing your holy symbol". Can you do other non-verbal actions while praying? Can you pray just in-your-head? Must your symbol be held in a hand?
For context, the party ventured into a great hall full of skeleton oathbreakers. Foolishly, they decided against running to a choke-point and engaging a couple at a time and instead waltzed right into the center of the room, prompting our Cleric to Turn Undead (successfully.)
However, her player then believed that she wouldn't be able to participate in combat and was visibly disappointed. This was with the assumption that brandishing the symbol would require the use of a hand and her only weapon was a two-handed staff. The party fortuitously found an amulet bearing a suitable holy symbol upon it that she could simply wear while turning undead and have both hands free, at least allowing the use of her staff.
Eventually, I ended up in an awkward spot where she was attempting many actions that seemed difficult to do in parallel with Turning Undead such as engaging in serious combat, evading rocks being thrown by skeletons outside of her range, and Spouting Lore (this last one we decided was impossible, even if she prays in her head because doing two things that involve language at once is nearly/completely impossible for humans in real life.)
One solution I can think of to address this is to require Defy Danger on all kinds of moves as she must focus on praying while participating in otherwise mundane activities.
Another is to disallow many actions to the chagrin of the player.
Finally, I could just allow it all but that may make undead encounters too easy, or worse, uninteresting. (She has 18 Wisdom so failure isn't very frequent for her.)
What do you do in this circumstance? Supposing there is an absence of explicit rules, what makes the game interesting and exciting for a Cleric wishing to Turn Undead?