When the additional alif and nun occur at the end of a proper name, the name is ghayr munsarif.
عُثْمَانُ and نُعْمَانُ are the established examples.
The two causes are proper-name status and additional alif-nun.
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Situation 1: At the End of a Proper Name
Cause of Ghayr Munsarif: Additional Alif and Nun
When the additional alif and nun occur at the end of a proper name, the name is ghayr munsarif.
عُثْمَانُ and نُعْمَانُ are the established examples.
The two causes are proper-name status and additional alif-nun.