وَيَوْمَ تَقُومُ السَّاعَةُ ... مَا لَبِثُوا غَيْرَ سَاعَةٍ
When the Hour is established ... they will say they remained only an hour.
The first sāʿah denotes the Final Hour, the second a span of time. Complete jinās requires sameness in letter identities, number, vocalic form, and order alongside difference of sense.
Different meaning is indispensable; even one altered formal condition can move the example to another class.