obligatory.

1. Required by a duty, obligation or binding expectation.

2. Conventionally expected as part of a familiar pattern, sometimes described with light irony.

Use it for

Words that belong together

• obligatory payment
• obligatory procedure

On the page

The obligatory payment followed from the agreement rather than a voluntary contribution.

The procedure was obligatory once the relevant conditions were satisfied.

Usage notes

Primary category: academic / formal. Forms: Normally non-gradable for a specified formal status; compare degree only where the context genuinely concerns a gradable capacity or characteristic. Legacy lexical fields mirror sense 1 only. Use numbered sense fields for all meanings. Established modern English lexical item. No separate regional spelling or grammatical inflection entry. Writing functions: status distinction, institutional analysis, scope qualification, rights analysis. Disciplines: formal writing, institutional procedures, legal-administrative language. Commonness: moderately common.