I couldn't miss the chance to practice my drawing!
Despoil is a Thief Job ability. It is an enhanced version of Steal, allowing the thief to cause a status ailment on the target while they steal an item. The status effect is based on the item stolen. Despoil shares a 5 minute recast timer with Steal, allowing the thief to use one of the two every five minutes.
Thief has access to "Despoil" as its Job Level 16 ability.