If you have Great weapon Fighting Style and are wielding a Two-handed melee weapon (or Dual Wielder Fighting style & wielding two melee finesse weapons) you can use your reaction to deflect the missile with your weapon when you are hit by a ranged weapon attack. When you do so, the damage you take from the attack is reduced by 1d10 + your Strength modifier (or Dexterity modifier if using finese weapon & duel wielding) + your Fighter level. If you reduce the damage to zerio (0) you deflect the missle.