In general FFXI speak, a useless Paladin that focuses on something other than tanking (a Paladin's strongest area)
In The Iron of Yin and Yang, it's the name of a perverted Hume Paladin (Thief sub) who focuses on offense and lolols way too much. His existence is very annoying without any redeeming traits to go with it. Seems to like Reimu, calling her "Reimu-tan".