Learned Sidestep

you've trained with an individual that had nearly a supernatural ability to have even the deadliest of attacks to be reduced to a glancing blow.

When an attacker that you can see hits you with an attack, you can use your reaction to halve the attack's damage against you.

This takes a lot of strenuous mental and physical exertion.

You can use this feature a number of times equal to your proficiency bonus. You regain all uses of this ability after a long rest.