Does Polearm Mastery have a disadvantage on adjacent targets?

Question

Does a character that has taken the Polearm Mastery feat have any trouble with targets closer than 10 feet? i.e. standing immediately in front of them (5ft).

The feat wiki tells me this:

Polearm Master: You can keep your enemies at bay with reach weapons. You gain the following benefits:

When you take the Attack action and attack with only a glaive, halberd, or quarterstaff, you can use a bonus action to make a melee attack with the opposite end of the weapon. The weapon’s damage die for this attack is a d4, and the attack deals bludgeoning damage.

While you are wielding a glaive, halberd, pike, or quarterstaff, other creatures provoke an opportunity attack from you when they enter your reach.

It says that it keeps them at bay, does this mean no creature can get closer to attack it?

I'm thinking about something along the lines of Ranged Weapons, where when a target is adjacent (5 ft.) you have disadvantage when trying to hit them.

Aiming a ranged attack is more difficult when a foe is next to you. When you make a ranged attack with a weapon, a spell, or some other means, you have disadvantage on the attack roll if you are within 5 feet of a hostile creature who can see you and who isn’t incapacitated. (BD&D p73)

Does this make sense? I want my players to have fun using their feats but I was curious if the rules say something about this specifically.

Answer 1

A player wielding a polearm weapon such as a glaive does not suffer from disadvantage when attacking an adjacent (5' away) enemy.

Reach
This weapon adds 5 feet to your reach when you attack with it, as well as when determining your reach for opportunity attacks with it.

All a reach weapon does is increase your melee attack range by an additional 5'. It becomes a Melee Attack with a reach of 10'. It does not become a Ranged Attack.

Polearm master then allows you to make opportunity attacks on enemies who enter your reach, in addition to the normal condition of making opportunity attacks against enemies who leave your reach.

While you are wielding a glaive, halberd, pike, or quarterstaff, other creatures provoke an opportunity attack from you when they enter your reach.

The bit about "keeping your enemies at bay" is simply a bit of text describing the general effect of the polearm master feat and has no direct impact on its own with regard to how polearm weapons are used.

The feat helps polearm users keep enemies at bay by allowing them to make opportunity attacks against approaching threats, not just fleeing threats. Once they have moved within reach and suffered any opportunity attack they can keep moving to close to 5 feet.