An ill-defined lesion margin is described as:
Ill-Defined Borders:
Blending Border: A blending border is a gradual, often wide zone of transition between the adjacent normal bone trabeculae and the abnormal-appearing trabeculae of the lesion.
Oral radiology White and Pharaoh; 7th ed. Page no 276
Sclerotic
Blending
Corticated
Punched out