Is a creature's bonus action available while affected by Turn Undead?

Question

There are a few features like Turn Undead which state:

A turned creature [...] also can’t take reactions. For its action, it can use only the Dash action or try to escape from an effect that prevents it from moving. If there’s nowhere to move, the creature can use the Dodge action.

It seems like this effectively removes a creature's reaction and action, but it never says anything about its bonus action. Does this mean that a creature affected by Turn Undead still has its bonus action available for use?

Answer 1

Yes you still have a bonus action

The important part of this, emphasis mine, Bonus Action (PHB Pg. 189):

You choose when to take a bonus action during your turn, unless the bonus action’s timing is specified, and anything that deprives you of your ability to take actions also prevents you from taking a bonus action.

You are not deprived from taking your action in the scenario you presented. It's simply limited to Dash or Dodge. This does not restrict bonus action usage such as casting a spell with a casting time of a bonus action, or using a rogue's bonus action to disengage, dash or hide, or anything else really.

Being forced to do something with an action is not the same as being deprived of the ability to use that action. If you want to deprive somebody of their action, you need to stun, paralyze or otherwise render them unconscious.

Answer 2

Yes, but...

The only part of the Turn Undead text which applies to bonus actions is the following:

A turned creature must spend its turns trying to move as far away from you as it can, and it can’t willingly move to a space within 30 feet of you.

If the creature has a bonus action that would allow it to get further away from whomever turned it, I would rule that it could (or perhaps had to) take that bonus action. Any other bonus actions would mean that it spent (part of) its turn doing something which was not moving as far away as it could.

On the other hand, dimension door would be a great way to get away from the one who turned. Since the target cannot use its action for that, one might rule that a turned creature is too shaken to concentrate on casting a spell.