الاسم المبني - Indeclinable Ism
With respect to declension of words, there are two categories of ism: الاسم المعرب and الاسم المبني. This article will discuss the second type, الاسم المبني
Declension is the changing of the form of a word to express its grammatical relation to other words in the sentence. In Arabic, these changes occur at the end of words. There are two categories of ism with respect to whether these changes are visible at the end of a word:
الاسم المعرب - words whose endings do change
الاسم المبني - words whose endings do not change
This article will deal with the second category.
Definition of الاسم المبني
هو الذي لا يتغيَّر آخرُه بتغير التراكيب
It is an ism whose ending does not change with the changing of the construction [of the sentence].
Another way to put it: الاسم المعرب is a word that, depending on its purpose in the sentence (e.g. whether it is a فاعل, مفعول به, مبتدأ), its ending will change. However, for الاسم المبني, their ending will remain the same no matter what its purpose is in the sentence.
For example, the word الّذين is considered الاسم المبني. Let’s see it in different sentences:
Notice how despite the word because in different states in all three scenarios, it still looks the same.
What are the ḥarakāt that remain affixed on الاسم المبني?
الاسم المبني remain affixed on one of three ḥarakāt or sukūn:
Ḍamma
For example: حَيثُ is considered مبني على الضمّ (affixed upon a ḍamma)
Fatḥa
For example: أينَ is considered مبني على الفتح (affixed upon a fatḥa)
Kasra
For example: هَؤُلاءِ is considered مبني على الكسر (affixed upon a kasra)
Sukūn
For example: ْمن is considered مبني على السكون (affixed upon a sukūn)
Types of الاسم المبني
There are eight categories of الاسم المبني:
المُضمَرات: pronouns (e.g. نحنُ)
أسماء الإشارة: indicating nouns (e.g. هذا)
الأسماء الموصولات: relative nouns (e.g. الذي)
أسماء الأفعال: nouns in the meaning of verbs (e.g. هيْهات)
الأصوات: certain noises (e.g. غاقِ)
المركّبات: nouns joined together (e.g. أحدَ عَشَرَ)
الكِنايات: indication (e.g. كَيتَ)
بعض الظروف: some adverb of time/place
And Allāh knows best.
Source: Hidāyat al-Nahw m’a As’ilatin wa Ajwabatin bil Lughatil Angalaziyyah