The game uses various ways of describing a physical melee attack:
- Melee Weapon Attack
- melee attack with/using a weapon
- attack with/using a melee weapon, or attack with/using a weapon (without the melee descriptor)
- weapon attack
- melee attack
Some of the descriptions are less restrictive than others, like a "melee attack" can include a spell attack, or a "weapon attack" can include a ranged attack. But for the scope of this question, let's consider physical and melee only (no spells, no ranged).
Question: Assuming there are no further restrictions, such as requiring a specific weapon property (like finesse or heavy), or a specific damage type, then are all of these attack descriptions identical, i.e. they are interchangeable? If an attack satisfies one of these descriptions, can it be used for any other description? If they are not identical, how are they different?
The genesis of this question began when considering the various use-cases in which an unarmed strike can be used in place of an attack. The rules say that an unarmed strike can be used as a melee weapon attack. Then I started considering whether an unarmed strike could also be used in place of a generic "weapon attack," which would only be the case if a "melee weapon attack" is identical to a "weapon attack" at melee. But instead of asking this specific question, I wanted to pose the question more generically such that I don't limit it to one specific instance, but rather create a general rule to help me answer future use-cases.