«مانع يمنع انعقاد العلة، كبيع الحر والميتة والدم»
One impediment prevents an effective cause from being constituted, illustrated by purported sale of a free person, carrion, or blood.
These examples lack the legally qualifying subject matter for the relevant sale, so the ordinary legal basis of a sale does not form.
An impediment to formation operates before the essential legal relationship is established; it does not merely suspend a consequence of an otherwise qualified transaction.