Stunlock and Blocklock
Stunlock
If an enemy does enough damage, you will be hit so that you cannot move and your character displays a stun animation.
During this animation you cannot move. That is called stunlock.
To avoid being stunlocked advance carefully, only fight two enemies in melee combat at time.
Blocklock
If your dexterity is high enough to block an enemy attack, you will block it with your shield.
But if you are swarmed by enemies, you will block endlessly. And during blocking you cannot defend against other enemies
other than the one you are blocking. Eventually, you are killed.
Also, avoid this by taking on two enemies at time.