5 enemies incapacitated with dodge counter.
To use a dodge counter, you must first obtain the skill through the Brawler skill tree. There are upgrades for this, but you don't have to worry about not being able to get the achievement if you upgrade. They still count. To use this skill, when a melee enemy attacks you, press B to dodge, and then the y when prompted.

Note: This must be done to different enemies. You cannot repeat this over and over again on the same enemy.