Some more information would be helpful.^^ … Where do you experience that it is blurred? In the background or in a reflection?
If it´s in the background it should not be blurred unless you purposly set it to be, or maybe the HDRI you are using is simply too low resolution? Did you try a different HDRI? – If it is blurred in the refelection then you can adjust the “Roughness” in the material node to change how blurry the reflection should be.