So, I changed class to Scout a few days ago, and put 1 skill point into Flu Flu. I haven’t used it much, because I wasn’t sure what it does. I asked other scouts too and they weren’t sure either. 
One said he thinks it’s like a provoke skill.
Pretty much everywhere I read says that fear makes the enemy run away, or not approach you. For example here: http://wiki.tosbase.com/wiki/Status_Effects#Fear
But, when I used Flu Flu on a mob, they mostly ran towards me lol 
So I really had no idea what it did.
But then today, I saw this description for fear, which seems to have been auto translated from Korean: http://www.tosbase.com/database/status-effects/9019/
Hmm! So I decided to try it out. I took off some of my leather armor to lower my evasion. I had some trouble making a clear video of it happening, but it seems like Flu Flu fear halves enemies attack for 8 seconds. It does not cause them to run away. You can see them hitting me for around 90-120+ dmg, and then when afflicted by fear, one hit me for 44 dmg.
I noticed in some games, fear also cuts your defense in half, but i didn’t notice myself doing any extra damage. (But I didn’t thoroughly test it.)
https://www.youtube.com/watch?v=5OZIJAcpIs4
And confuse seems to work as described. I guess the monster attacks the closest target. Monsters who were attacked may change target. So the targeted monster has 3 status effects on it. Confuse, Fear, and an effect called Flu Flu. I’m not sure if it does anything extra, but here is a description:
