Relating to or characteristic of a constable or constables; concerning the office or duties of a constable.
From constable + -ar (adjectival suffix from Latin). The -ar ending creates adjectives meaning 'of or relating to,' similar to 'angular' and 'popular.'
Constabular is a scholarly adjective rarely used today, but it shows how English can turn any noun into an adjective—legal documents might say 'constabular duties' to mean duties specific to constables.
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