Question

what does mild lateral downsloping of the acromion process meaning

Answer 1

Acromion is the upermost part of the shoulder blade (scapula), which is a paired flat bone in your upper back.

Mild lateral downsloping of the acromion means a mild misalignment of the scapula, which may be an anatomical variation and, if it does not cause any symptoms, is not a "disorder".

You can check for causes of shoulder blade pain here.