Geralt can evade attacks by enemies in different ways: Dodging and Rolling.
While holding an item in his left hand, such as a torch, Geralt cannot counterattack. Counterattacking and parrying is most effective against humans and nonhumans, due to them utilizing melee weapons during combat, however two-handed weapons such as pikes cannot be parried. The counterattack will knock the enemy off balance, allowing a few ripostes. Geralt can also perform a counterattack by pressing the Parry button right before an enemy's attack strikes him. Parrying attacks is an easy defensive maneuver that can help absorb some damage. Weak opponents are not able to parry strong attacks, but relying on them too often could leave Geralt open for punishment. Strong attacks are slow, but powerful attacks that deal significant damage. They don't inflict very much damage, but can be important for maintaining your offensive flow. Fast attacks are quick strikes that can be strung together easily into long combos. There are two types of attacks, fast attacks and strong attacks.