وَيَجِبُ تَجْرِيدُ الْمُضَافِ عَنِ التَّنْوِينِ أَوْ مَا يَقُومُ مَقَامَهُ.
Translation: The mudāf must lose tanwīn, or what functions in its place.
غُلَامٌ (a standalone indefinite noun) becomes غُلَامُ زَيْدٍ (a mudāf).
The tanwīn disappears; one ḍammah remains when the mudāf is nominative.
This omission follows from iḍāfah; it does not mean the noun has become diptote.
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Al-Majrūrāt — Semantic and Formal Iḍāfah
وَيَجِبُ تَجْرِيدُ الْمُضَافِ عَنِ التَّنْوِينِ أَوْ مَا يَقُومُ مَقَامَهُ.
Translation: The mudāf must lose tanwīn, or what functions in its place.
غُلَامٌ (a standalone indefinite noun) becomes غُلَامُ زَيْدٍ (a mudāf).
The tanwīn disappears; one ḍammah remains when the mudāf is nominative.
This omission follows from iḍāfah; it does not mean the noun has become diptote.