Grammar term · Sarf · morphology
إِعْلَال بِالْحَذْف
i'lal bi-l-hadhf
Weak-letter deletion (i'lal by hadhf)
Sarf · morphologyMorphophonemic processadvanced term4,992+ in the Qur'an
In one line
Weak-letter dropping: the weak letter is deleted outright for lightness — وَعَدَ keeps no waw in يَعِدُ.
Classical definition
الإِعْلَالُ بِالحَذْفِ إِسْقَاطُ حَرْفِ العِلَّةِ تَخْفِيفًا، كَحَذْفِ الوَاوِ فِي يَعِدُ.
“I'lal by deletion is the dropping of the weak letter for lightness, like the deletion of the waw in ya'idu.”
(بتصرف من شذا العرف)
Key words in the Arabic
إِسْقَاطdropping, deletion
تَخْفِيفًاfor lightness
Understand it
Sometimes Arabic doesn't bend the weak letter — it removes it. The mithal loses its waw in the mudari' (يَعِدُ، يَجِدُ); the naqis loses its tail in jazm and amr (لَمْ يَدْعُ، ٱرْمِ); the ajwaf shortens in closed syllables (قُلْتُ from قال، لَمْ يَقُلْ). For the reader the crucial habit is the reverse operation: a two-letter verb form always had a third letter — find what dropped and you find the root.
How to spot it
Recognition test
A verb form with fewer letters than its root: hadhf. Check the position — start (mithal mudari'), middle (ajwaf before sukun), or end (naqis in jazm/amr) — and restore the missing radical to identify the root.
In the Qur'an
يَعِدُهُمْ وَيُمَنِّيهِمْ
An-Nisa 4:120 — “He makes promises to them and gives them false hopes”
يَعِدُ from وَعَدَ — the root waw has been deleted for lightness: i'lal bil-hadhf, the mithal's signature.
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