Item attunement
Item attunement occurs when an item is attuned, or locked, to either a character or an account. This can occur through various means and outside of certain circumstances, cannot be removed.
Script Attunement
Script attunement occurs when an item attunes due to a script, and this can be either permanent attunement or temporary. If temporary attunement, some additional steps may be necessary to clear the attunement. If permanent, the attunement is set at the first point of initial use and cannot be removed by any means. For a list of scripts that attune, please see attuning item scripts.
Weapon Bonding
Weapon Bonding is a skill available to warriors, while paladins have access to the spell Holy Weapon (1625), which creates the same affect while simultaneously turning their weapon into a holy armament. Weapon bonds are considered temporary as warriors and paladins can opt to break their bond for either a new weapon, or in the case of paladins, ease of player service additions.
Once a weapon is bonded, it is unusable by anyone else, and when fully bonded, is able to return to the proper wielder should it ever be disarmed.
Purchase Attunement
Purchase attunement occurs at the time of purchase. This tends to happen primarily at pay events, in particular, Duskruin Arena, in which the purchase option for ATTUNE allows for a discount on the item. This will set the item's attunement is typically set up for the account and is permanent, therefore, it cannot be removed.
This includes certificates that may be used to apply a service to an item. Once that service is applied and complete, it attunes the item to the account or character and cannot be removed at any point.