[RPG] What does the Swarmkeeper mean by “horizontal”

dnd-5eforced-movementranger

The Ranger Swarmkeeper Gathered Swarm has 2 ability's that can force horizontal movement. But how do they work?

The attack's target must succeed on a Strength saving throw against
your spell save DC or be moved by the swarm up to 15 feet horizontally
in a direction of your choice

Is this horizontal from the direction I am facing, and if so what is stoping me from turning myself to aim freely, or is it horizontal from where the monster is facing? And second we have…

You are moved by the swarm 5 feet horizontally in a direction of your choice.

What's stopping me again from changing my direction to move freely here too?

Basically can I cheese this to push monsters either CLOSER or FURTHER away from me, not just left right movements.

Best Answer

Horizontal is defined with respect to some absolute reference frame, not the reference frame of the ranger.

This answer is adapted from my answer here to a question about tiny hut and caster orientation.

To be clear, there is no RAW definition of horizontal, so we interpret it in the usual way that horizontal is used in English.

Relevant definitions of horizontal all read similarly to this one:

horizontal: parallel to the plane of the horizon

To an observer watching this feature at work, the notion of horizontal is irrelevant of the ranger's orientation.

More importantly, the ranger should agree with this observer, since horizontal is defined with respect to the horizon, not the ranger or the observer.

Or, as Ryan Kinal mentioned in a comment on your question:

Laying down doesn't change what is horizontal. It changes whether you're horizontal.

The ranger is not aware of the text of the feature description.

The feature description is meta-knowledge, and trying to leverage it to get horizontal to mean "any direction you want" is metagaming. The ranger does not know that the feature description text says horizontal - this is strictly player knowledge.

The ranger only knows that their ability pushes stuff sideways.