Adat
From Indonesian, Malaysian and related legal systems
Religious and customary law
What it means
Local custom that governs family, land and community life, and that the law in several countries recognises. The word comes from Arabic but has a local meaning in Southeast Asia.
Why it travels badly
'Customary law' makes it sound like one body of rules. In fact adat differs between communities, is often unwritten, and changes over time. The Dutch colonial lawyers made 'adat law' an academic subject, which changed how it is understood.
How other systems say it
hukum adat
Recognised alongside statute and Islamic law, especially for land and family matters.
adat
Customs that operate in particular communities and states, such as Adat Perpatih in Negeri Sembilan.
Tip for translators and students
Keep 'adat' and add 'the customary law of the community concerned', since the content changes by place.
Related: Waqf
Updated October 2026. Spotted a mistake? Tell us.
TheLawToKnow Tools’s glossary is an educational overview of the main differences between legal systems. It is not legal advice.
