How doess Feint work ?

Feint : Atk with potency of 120, additional effect +20% slow.

What is the way +20% slow work ?
1. Target reduced movement speed
2. Target reduced number of auto-attack
3. Target reduced skill cast time
4. Target reduced ____________

Thanks ^^

Skill cast time/auto attack speed.




Edit:

Heavy and Disease are the move speed debuffs. Disease is also a 50% healing debuff.

Thanks, it should be useful in some situation :)

i find it useful on the flan boss of WP, hit it with feint, and when he casts fire it will take longer, and when he finishes casting, he will cleave imediatly