Definition
A prohibition or forbidden act. In Jewish law (halakha), an issur is any act, object, or conduct that is prohibited — either by biblical commandment or by rabbinic decree. The term functions as a general category encompassing the full range of religious-legal prohibitions, from dietary restrictions to Sabbath observance rules to forbidden relationships. In legal contexts outside Jewish law, the term appears rarely and almost exclusively in discussions of Jewish legal doctrine or comparative religious law.
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Common Language
Modern common usage (Wiktionary): "A prohibition; something forbidden."
Historical common usage (Webster's 1913): Not attested. The term does not appear in Webster's 1913 general dictionary, reflecting its status as a term of art from a specific religious-legal tradition rather than general English usage.
The common usage here tracks the legal meaning closely — both mean "a prohibition." The gap that matters for researchers is not semantic but contextual: the everyday gloss captures the surface meaning but omits the doctrinal structure of Jewish law, where issurim (plural) are formally categorized by source, severity, and the mechanism by which they are imposed. Knowing something is "forbidden" tells you little about which authority forbade it, how violations are treated, or how the prohibition interacts with competing obligations.
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Why It Matters in Research
Researchers encounter this term almost exclusively in one of three contexts: (1) scholarly or comparative treatments of Jewish religious law appearing in academic legal journals; (2) ecclesiastical or religious arbitration disputes where Jewish law governs the parties by agreement; and (3) historical legal texts addressing the status of Jewish communities and their internal governance under civil law frameworks.
The primary research trap is terminological isolation. Because issur is not a term of English common law, it appears in the Law Mind corpus largely in secondary sources — law review articles, treatises on religious arbitration, and comparative jurisprudence — rather than in case law or statute. A corpus search limited to case reporters will return little. Expanding to journals, encyclopedia entries on religious law, and arbitration materials is necessary.
A secondary trap involves the plural form. The plural issurim is used as frequently as the singular, and researchers should search both forms. Variant transliterations (issur, issur, isur) also appear depending on the source's transliteration conventions.
For researchers working on the intersection of religious law and civil enforcement — particularly in the context of Jewish divorce (get), dietary certification (kashrut disputes), or Sabbath employment contracts — issur and its application will often be the operative legal concept even when civil courts decline to adjudicate it on First Amendment or ecclesiastical abstention grounds.
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Historical Dictionary Support
Black's Law Dictionary (2nd Ed.) does not contain a standalone entry for issur. The source fragment provided in the reference material is unrelated — it describes resolutive clauses in property deeds under Scots or civil law, which appears to be an extraction error rather than a substantive definition.
This absence is itself significant. The omission from Black's reflects the historical editorial scope of Anglo-American legal dictionaries, which did not systematically incorporate Jewish legal terminology even when such terms were relevant to cases involving religious arbitration or communal governance. Researchers should not interpret the absence from standard common law dictionaries as evidence that the term lacks legal content — only that its doctrinal home lies elsewhere.
For substantive historical treatment, researchers should consult encyclopedias of Jewish law (particularly the Encyclopedia Talmudit), comparative religious law scholarship, and secondary legal literature on religious arbitration rather than Anglo-American dictionary sources.
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Jurisdictional Note
Issur as a category of Jewish law has no direct standing in any civil legal system, but it becomes relevant in jurisdictions that permit or enforce religious arbitration agreements. United States courts, Israeli civil courts, and English tribunals have each grappled with the enforceability of decisions rooted in halakhic prohibitions, with results varying by jurisdiction and the specific nature of the dispute.
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