I couldn't miss the chance to practice my drawing!
Weakened is a status that is automatically given to a player for a period of 5 minutes after they had been revived from a KO'd status by a Raise spell. This period of time can not be reduced by any means, either by a Cursna or Haste. A Weakened status will reduce a players HP and MP by 75%. It may also reduce a character's overall fighting ability for that period of time.
That if a character chooses to return to their Home Point upon being defeated, Weakened will not occur, but the player forfeits the regained experience from being Raised.
Players who participate in Dynamis will also receive a weakened status should they exit and reenter. This status lasts longer than if the player had actually died. This is, presumably, to discourage people from exiting—probably thought to be a good way to avoid the death of all alliance members at one point when something goes wrong in Dynamis.
If a player with the Weakened status were to have their HP reduced to 0 a second time and revived, they will suffer from an advanced version of Weakened that cripples their ability to deal damage until the it fades.
A small number of monster special attacks can also inflict the status, although it does not last as long as when it is inflicted by death. Dying with this form of Weakened inflicted will mean that the player will suffer the advanced Weakened described above. Some of these monsters include Naraka family Notorious Monsters with the attack Raksha: Vengeance, the Iron Giant NM Voidwrought with the attack Eradicator, and Provenance Watcher's attack Fragor Maximus.
The Great Axe Himthige has the special property of rarely (less than 10% of the time) negating this status. The duration of the status from being being raised after KO will be reduced to 3 minutes if the player is raised with Arise.
A defeated player that is revived with a Raise spell will be placed under the Weakness status and have their Strength, Dexterity, Intelligence, and Mind stats reduced by 25% for a 1 minute 40 seconds duration. Being knocked out while under Weakness and being revived a second time will put the player under the Brink of Death status, which reduces Strength, Dexterity, Intelligence, and Mind stats by 50% for 1 minute 40 seconds. A player who is knocked out and chooses to return to their home point or to the beginning of the dungeon will not incur the Weakness/Brink of Death status.
While Weakness and Brink of Death cannot be removed, the Free Company action "Back On Your Feet" can reduce the duration of the status effect.