What does 'Stun' do anyways?

[Sir PotsNPans]

My party is currently Lv 20, and I still don't understand exactly what Stun does. Notably, I was fighting Warped Wolves, and have a character with the Stunning Blade. I hit the Wolf four times, and it said it was Stunned four times.

But when its turn came up (wasn't skipped), it still attacked me twice. The Stunning Blade seemed like a good tradeoff for my dual-wielder if it helped CC enemies, but Stun doesn't seem to do anything, even with something crazy like this 4x Stun on one enemy.

Does anyone know what Stunning does exactly? Or if it's worth investing a whole weapon into?