You use your reaction to dodge, allowing your next attack against you to be rolled with DIS.
While not as powerful as Dodge, it does allow any creature to reduce a potential attack against them.
You glimpse the blade’s glint, muscles coiling. A blur of motion—your body twists, air hissing past. The steel grazes your cloak, missing flesh. You pivot, unscathed, dust swirling in your wake.