No Assassin job. Ninja/Thief has always been the FF 'Assassin' job with abilities like Sneak Attack, Trick Attack, Assassinate, Hide, and in FFXI THF got a trait that was literally called "Assassin", as well as AF2 armor that was called "Assissin's Attire" (and an AF3 called "Raider's Attire" which resembled Assassin's Creed with a white hood!)