What weapons are eligible for two-weapon fighting?

Question

Page 146 of the PHB lists some of the most common weapon properties. Page 195 of the PHB goes over the rules for two-weapon fighting, stating that you must be holding a weapon in both hands – both of which must have the "light" property. The Dual Wielder feat on page 165 further modifies this by saying that the weapons you may use for two-weapon fighting don't need to be light.

The issue I'm running into is that the Dual Wielder feat specifies that the weapons must be "one-handed" even though there's no such weapon property as "one-handed".

Does this mean that one can use any weapons that may be used with one hand (including versatile weapons)? Or must the weapons lack both the two-handed and versatile properties (meaning the weapon must be exclusively used with one hand)?

Answer 1

Here's another way to think about it.

The "Dual Wielder" feat only removes the "light" requirement from the wielded weapons. You still need to take the Attack action, and that attack must come from a weapon held in one hand. Effectively, it modifies the two-weapon fighting rules as follows:

When you take the Attack action and attack with a light melee weapon that you’re holding in one hand, you can use a bonus action to attack with a different light melee weapon that you’re holding in the other hand.

Emphasis mine.

Two-weapon fighting + Dual Wielder doesn't care about weapon properties at all. If you, for example, somehow gain the ability to wield and attack with Greatsword one-handedly, it would also be viable for use with your Dual Wielder-enhanced two-weapon fighting.

In short, Versatile weapons are totally valid to be used with the Dual Wielder feat (though, since you're wielding it one hand, you'll never benefit from the Versatile property itself). As long as you can attack with the weapon (and one-handed one-hand-wielded Versatile weapons fit the bill), it's valid thanks to Dual Wielder.

Answer 2

The wording of the dual-wielder feat 'even when the one-handed melee weapons you are wielding aren't light' makes it clear 'one-handed' is not adding a restriction, but preserving an existing one.

The two-weapon fighting rule quoted by Raven Dreamer makes it clear what 'one-handed' means in this context: it means you are holding it in one hand at the time.

So in the feat decription 'one-handed' is largely redundant, but it serves to nail down unusual cases such as a four-armed creature wielding two scimitars and a greatsword.