أبواب الفعل الثلاثي — The Six Verb Families
All sound triliteral Arabic verbs (فعل ثلاثي مجرد صحيح) are divided into six families (أبواب, abwāb; sing. bāb) based on the vowel on the second radical in the māḍī and how it changes in the muḍāriʿ.
Why Six Families?
Unlike other morphological patterns, there is no predictive rule for which vowel the second radical takes in the muḍāriʿ. The vowel pattern must simply be memorized — or looked up in a dictionary. The six families organize all possible combinations.
The Six Families
| Family | Māḍī Vowel | Muḍāriʿ Vowel | Full Pattern | Classical Name | Example Verb | Meaning |
|---|---|---|---|---|---|---|
| a → a | fataḥ | fataḥ | فَعَلَ / يَفعَلُ | بَابُ مَنَعَ | مَنَعَ / يَمنَعُ | to prevent |
| a → i | fataḥ | kasra | فَعَلَ / يَفعِلُ | بَابُ ضَرَبَ | ضَرَبَ / يَضرِبُ | to hit |
| a → u | fataḥ | ḍamma | فَعَلَ / يَفعُلُ | بَابُ نَصَرَ | نَصَرَ / يَنصُرُ | to help |
| i → a | kasra | fataḥ | فَعِلَ / يَفعَلُ | بَابُ شَرِبَ | شَرِبَ / يَشرَبُ | to drink |
| i → i | kasra | kasra | فَعِلَ / يَفعِلُ | — | (rarer) | — |
| u → u | ḍamma | ḍamma | فَعُلَ / يَفعُلُ | بَابُ كَرُمَ | كَرُمَ / يَكرُمُ | to be noble |
Reading These in a Dictionary
Arabic dictionaries often indicate the family with abbreviated notation alongside the verb entry. For example: - (a a) = māḍī fataḥ, muḍāriʿ fataḥ → بَاب مَنَعَ - (a i) = māḍī fataḥ, muḍāriʿ kasra → بَاب ضَرَبَ
The Special Family: فَعُلَ / يَفعُلُ
The u → u family (bāb karuma) is unique in meaning among the six. It is specifically used for inherent, ingrained characteristics — qualities a person either has or does not have, which cannot be switched on and off:
| Verb | Meaning | Why This Family |
|---|---|---|
| كَرُمَ | to be noble | nobility is intrinsic — you cannot be noble sometimes |
| شَرُفَ | to be lofty/honorable | honor is constant |
| عَظُمَ | to be great | greatness is not momentary |
| حَسُنَ | to be beautiful/good | inherent quality |
The Test
Can you stop doing the action for a while? Sitting — yes. Being hungry — yes (hunger passes). Being noble — no. If the quality is either present or absent as an intrinsic trait, the verb belongs to this family.
Two Distinctions of This Family
- Semantic: only used for inherent/continuous characteristics
- Morphological: the ism fāʿil is on فَعِيل (not فَاعِل) — see Faʿīl Pattern
Examples from the Quran
| Āyah | Verb/Adjective | Family | Notes |
|---|---|---|---|
| وَأَجرٌ عَظِيم (Al-Ḥujurāt 49:3) | عَظِيم | u→u / فَعِيل | The reward's greatness is undiminishing |
Session References
- Surah Al-Hujuraat Session 5: Introduction to all six families; special semantic property of فَعُلَ/يَفعُلُ; ism fāʿil as فَعِيل; application to عَظِيم in Āyah 3.