The attacks of all melee weapons are broken up into multiple phases, each with their own distinct durations in milliseconds. You can find out the details of each individual weapon on their respective pages. Phases italicized are "secret" phases, with lengths not detailed in-game, and generally unknown.
Windup[ | ]
The beginning of the attack. This phase of varying length telegraphs to the opponent which attack direction you chose, and is where your setup for swing manipulation usually takes place.
If it is a neutral attack, you can feint, parry, or morph.
If it is a riposte, you can only parry.
Pre-Late Windup[ | ]
The attack can no longer be morphed. This generally occurs minimally before Late Windup, to allow feints to be stronger cancels than morphs.
Late Windup[ | ]
Your attack has been committed and can no longer be cancelled by you in any way.
Early Release[ | ]
Weapon begins moving, you begin to grunt, but damage isn't dealt. Enemies and terrain can block the attack during this phase, despite it not dealing damage.
If terrain is hit, the weapon will stop and go into recovery.
Release[ | ]
Your weapon will deal damage to anything it touches, stopping on teammates if they are not killed.
If the weapon can combo, an attack may be inputted during this phase to combo into from the opposite side.
If the weapon is blunt and an enemy was hit but not killed, a teammate was hit, or terrain was hit, the weapon will stop and go into recovery.
If an enemy was hit through, you can parry out before the phase ends.
Late Release[ | ]
Same as the normal Release phase, but very short, and you can input a parry to be executed the instant you are able to.
Combo[ | ]
If the weapon cannot combo, this phase will be skipped.
Same as the Windup phase, except it has its own length and animation, essentially a transition between end of release and your next attack's late windup.
Recovery[ | ]
If a combo was initiated, this phase will not occur.
Miss: Lose stamina based on your weapon, you are unable to input any attacks. If the weapon can combo, you may parry for the cost of a feint. This is known as "combo feint to parry" and used to require you to queue a combo first, but can now be done regardless.
Terrain Hit: Quicker, but you cannot parry or input attacks.
Player Hit: Far quicker. You can parry, but you are still unable to input attacks.
Parried: Quicker. You can parry, but you are still unable to input attacks.
Chambered: Quicker. You can parry, and you are almost instantly able to cancel this phase to start an attack in order to counter-chamber.