Faraid: the Fixed-Share System
Faraid (from the Quranic term fara'id, "obligatory shares") is the overall system of fixed inheritance shares laid out primarily in Surah An-Nisa (4:11–12, 4:176). Unlike a general common-law system where a will determines the entire distribution, Faraid pre-assigns fixed fractional shares to a defined set of relatives (spouse, children, parents, and others depending on who survives) before any question of a will even arises. It's the framework everything else in this glossary sits inside.
Wasiyyah: the Will, Capped at One-Third
A wasiyyah is the testamentary document itself, but critically, it only controls up to one-third of the net estate, and only for bequests to non-heirs. The cap traces to the hadith of Sa'd ibn Abi Waqqas (Sahih al-Bukhari 2742): "One-third, and one-third is much." The remaining two-thirds are already allocated by Faraid to classified heirs and cannot be redirected by the will. A bequest to someone who is already a classified heir is void by default under the hadith "there shall be no bequest for an heir" (Abu Dawud 2870), unless every other heir unanimously consents after the testator's death.
'Awl: Proportional Reduction
'Awl applies when the fixed Quranic shares of the surviving heirs add up to more than the whole estate: a real arithmetic possibility given how many shares are conditional on who else survives. The classical resolution, first applied during Umar ibn al-Khattab's (RA) caliphate, is to reduce every share by the same proportion so the total comes back to exactly one. Not every school accepts this: the Ja'fari school treats a fixed Quranic share as never reducible, and resolves the same shortfall differently (see Radd).
Radd: Return of the Surplus
Radd is the mirror case to 'awl: the fixed shares don't exhaust the estate, and there's no residuary ('asabah) heir left to absorb the remainder. Most schools return that surplus proportionally to the existing fixed-share heirs rather than letting it go unclaimed. Where the classical Shafi'i and Maliki position historically escheated the surplus to a public treasury, the prevailing modern position (and the one applicable in India, where no such treasury exists for this purpose) is to apply radd instead.
Hajb: Blocking and Exclusion
Hajb is the exclusion of certain heirs due to the presence of a closer relative. It comes in two forms: hajb bil-hirman, total exclusion (a paternal grandfather is blocked entirely by a living father in the Sunni schools), and hajb bil-nuqsan, partial reduction rather than full exclusion. The Ja'fari school applies a related but distinct mechanism: a three-tier class system (see Tabaqat) where an entire class of relatives is excluded by any surviving member of a higher class.
'Asabah: the Residuary Heirs
After the fixed-share heirs (ashab al-furud) take their Quranic portions, whatever remains of the estate passes to the 'asabah: residuary heirs, typically male agnatic relatives such as sons, then the deceased's father, then brothers, in a defined order of priority. The 'asabah system is why a son and a daughter in the same family can end up with very different totals: the daughter has a fixed fractional share, while the son often inherits partly as a fixed heir and partly as residuary.
Tabaqat: the Ja'fari Class System
Tabaqat means "tiers" or "classes." Rather than the Sunni schools' case-by-case blocking rules, the Ja'fari school groups all potential heirs into three ranked classes (broadly, (I) children and parents, (II) grandparents and siblings, (III) more distant relatives) where any living member of a higher class excludes the entire lower class outright, not just reduces its share. A single surviving daughter, for instance, excludes the deceased's siblings completely under this system, where a Sunni calculation would have them share the estate as residuary heirs.
Kalalah: No Ascendants or Descendants
Kalalah describes the specific case where the deceased leaves neither parents nor children. Surah An-Nisa (4:176) addresses this scenario directly, establishing distinct rules for how siblings inherit when the estate isn't already claimed by the more immediate family members who would otherwise take priority.
Hiba: Lifetime Gifts, Outside the Cap
A hiba is a gift made during the giver's lifetime, completed by an immediate, unconditional transfer of possession. Because it takes effect before death rather than through the estate, a hiba is not subject to the one-third wasiyyah cap and can be made to anyone, heir or non-heir alike. This is a genuinely separate mechanism from a bequest, not a workaround for the cap: a bequest promises a future transfer at death; a hiba is a completed transfer now.
Waqf: Charitable Endowment
A waqf is a permanent charitable endowment: an asset dedicated irrevocably to a religious, educational, or charitable purpose, with the asset itself preserved and only its usufruct (benefit) applied to that purpose in perpetuity. A waqf can be established during one's lifetime or via a wasiyyah's one-third discretionary share, making it one of the main channels for structured, lasting charitable giving within an Islamic estate plan.