وهو عبارة عن الفعل مع زيادة إحكام
It denotes an act with the added sense of precision or firm accomplishment.
In one usage, qaḍāʾ refers to bringing an event to completion in an ordered manner. In that sense it adds the notion of determinate accomplishment to the generic meaning of an act. Elsewhere it denotes a ruling or command, even if the addressee disobeys it.
Ordering an action, stating that the action occurred, and saying that it was completed at a specific time and in a particular manner are different propositions. Confusing these senses creates many of the later difficulties about what it means to accept divine decree.