Pretty frequently I'll be fighting an enemy and alongside all of the damage numbers that come flying up, I'll see the word "Vulnerable" popup above the enemy hitbox briefly.
What does this convey? Is this a term for staggering an enemy with your attacks? Is it a specific condition like poison?
If it matters, I've been playing almost exclusively in the Finesse tree, using Faeblades and Daggers (whatever I find a better one of at the time), with a heavy investment into the passive skill that allows me a chance to poison my targets.