What is the difference between "hostile" and "enemy"?

Question

What is the difference between "hostile" and "enemy"?

Why do I think there should be a difference? Well first off, they are different words. In dnd there is difference between attack and Attack action, so it's not unusual that small differences in words used are intentional. This alone hints they probably used the words on purpose where they used them.

Also I use them differently in daily use. I might act hostile towards someone that told a joke I don't like, but that doesn't make them my enemy. But of course daily life is not combat for life or death so that is a weak example.

Last, there are some game situations where in my opinion a difference makes sense. Let's assume the following situation:

We have characters A and B from the same party and C is a character hostile towards them, so an enemy of A and B. For now the words are synonymous. Now C casts "Enemies Abound" on B and B fails the save. He is now "regarding all creatures [he] can see as enemies until the spell ends.". Let's assume A hasn't noticed the spell. If A would now for whatever reason try to cast "Friends" on B, the spell should fail because B regards A as an enemy and is hostile towards him. Friends requires the target to not be hostile. However here A does not (yet) regard B as an enemy. So hostile and enemy are not the same. Contrary A is not hostile towards B so B could cast Friends on A, even though he considers A an enemy.

This makes sense to me so far. It is not limited to the spell "enemies abound", I think the same logic would apply if B was a hidden enemy in the party. Then B should be able to cast friends on A because A trusts him, but A should be not able to cast it on B because B is actually hostile towards him.

So when A interacts with B, whether B is an enemy is something A decides, however whether B is hostile towards A is something B decides. All good? No! This definition has other problems.

On PHB page 195 under opportunity attack it states:

You can make an opportunity attack when a hostile creature that you can see moves out of your range.

So in the example above B would not be able to make an opportunity attack against A because A is not hostile towards him. That makes no sense at all. B considers A an enemy and should totally be able to make an opportunity attack.

Also B could not target A with any spells that require A to be hostile.

Another example with opportunity attack:

An enemy courier has an important message in the bags of his horse. I push him off his horse, but the horse runs on on its turn (probably afraid). Can I make an attack of opportunity against the horse? The horse is probably not hostile towards me. So I can't? That doesn't make sense.

I hope I made clear why I am confused about the usage of "hostile" vs. "enemy". Maybe someone can explain me why they make this differentiation and what the differences are.

Answer 1

Ask your GM

Hostile means:

unfriendly; antagonistic; opposed.

Enemy means:

a person who is actively opposed or hostile to someone or something.

These have effectively the same definition, the uses of these words are nearly equivalent.

A GM would decide whether a creature is considered hostile or an enemy as there is no mechnical definition.

Answer 2

Hostile is how enemies perceive you, Enemy is how you perceive others

When the rules use the word hostile, it comes from the frame of reference of a creature that is not you.

Wand of Enemy Detection

For the next minute, you know the direction of the nearest creature hostile to you within 60 feet

Friends

For the duration, you have advantage on all Charisma checks directed at one creature of your choice that isn’t hostile toward you

Hat of Vermin

The creature is neither friendly nor hostile, and it isn’t under your control

Page 244 of the DMG.

A friendly creature wants to help the adventurers and wishes for them to succeed.

An indifferent creature might help or hinder the party, depending on what the creature sees as most beneficial.

A hostile creature opposes the adventurers and their goals but doesn't necessarily attack them on sight.

Now, notice you have no control over the hostility of other creatures.That's what hostility is. Other creatures attitude defines whether they are friendly, hostile, or neutral toward you.

So, hostile refers to attitudes towards you, enemy refers to really anyone your DM allows you to consider your enemy. Its not so simple as to claim any creature is your enemy, but it is something defined by your character and usually entails combat, whereas hostility can work outside of combat.

Answer 3

A creature can be hostile without being an enemy.

While it is all up to interpretation, type of campaign you are running, how combat heavy it is, along with many other things, a friendly or neutral PC or NPC can be "hostile" under the correct (and very simple) circumstances.

In my own form of RAI: The difference between Hostile and Enemy is that an enemy is counter to your alignment, goals, or other way of virtue that inhibits it from being your ally or even neutral toward you. A hostile creature (or other being) is something that means to do you harm, be it passively or directly, such as attacking you with a weapon or frying pan. This can definitely be a friendly who is intending to cause you harm (even if in a playful manner - which occurs quite a lot in my home campaign).

However, RAW indicates for "Hostile" (DMG Pg. 244):

A hostile creature opposes the adventurers and their goals but doesn't necessarily attack them on sight. For example, a condescending noble might wish to see a group of upstart adventurers fail so as to keep them from becoming rivals for the king's attention, thwarting them with slander and scheming rather than direct threats and violence. The adventurers need to succeed on one or more challenging Charisma checks to convince a hostile creature to do anything on their behalf. That said, a hostile creature might be so ill disposed toward the party that no Charisma check can improve its attitude, in which case any attempt to sway it through diplomacy fails automatically.

Unfortunately, there is no exact definition on what makes an "enemy" an "enemy", so feel free to adopt my own interpretation from above or develop your own beyond what is indicated in my answer.