Quote Originally Posted by RooSL
Esuna is pronounced "Es-na", so Kawaii Ryűkishi is probably right. It's either that or you take "esu" in Japanese, which means "sister", and think of it as Antisister.
Sister is the most feared status in any FF game. All characters afflicted with sister get no privacy, and have to put up with pink things lying around. Also, characters afflicted with sister have roughly a 1 in 10 chance of being blamed for something they didn't do.