mandatory
[adjective]
Synonyms: compulsory, binding, obligatory, required, requisite

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Antonyms: optional
Contrasted words: discretionary, elective, voluntary
Related Words: essential, indispensable, irremissible, necessary, needful, requisite, binding, commanding, compelling, de rigueur, forced, involuntary

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English Thesaurus: compulsory, obligatory, mandatory, optional, voluntary, ...

[TahlilGaran] English Synonym Dictionary ▲

man‧da‧to‧ry /ˈmændətəri $ -tɔːri/ adjective
if something is mandatory, the law says it must be done Synonym : compulsory, obligatory ⇒ discretionary
mandatory for
Crash helmets are mandatory for motorcyclists.
Murder carries a mandatory life sentence.
The Council has made it mandatory for all nurses to attend a refresher course every three years.

[TahlilGaran] Dictionary of Contemporary English ▲

compulsory if something is compulsory, you must do it because of a rule or law:
Maths and English are compulsory for all students.
Compulsory education was introduced in 1870.
Wearing a seatbelt is compulsory.
It is now compulsory for anyone claiming state benefit to register with a job centre.
obligatory [not usually before noun] if something is obligatory, you must do it because of a rule or law. Obligatory is more formal than compulsory:
It is now obligatory for all competitors to wear face protectors.
Evening dress is usual, but not obligatory.
Military service is obligatory for all men between 18 and 27.
mandatory if something is mandatory, you must do it because it is the law. Mandatory is more formal than compulsory and sounds stronger:
Drug smuggling carries a mandatory death sentence.
In some countries, wearing helmets is mandatory for all cyclists.
optional if something is optional, you can choose whether to do it or not:
You don’t have to do French – it’s optional.
The holiday price includes optional excursions such as an evening cruise on the lake.
General Studies is optional for sixth-form students.
voluntary done because you want to do it and not because you have to – used especially about things that you do because you think they will help other people or be useful:
The programme is entirely voluntary, and no one will be forced to join.
The charity is funded by voluntary donations.

[TahlilGaran] English Thesaurus ▲

necessary used to describe something that you need to have or do:
Make sure you bring the necessary documents with you.
It may be necessary for you to have a small operation.
essential very important and necessary, especially in order to be healthy, successful etc:
Vitamins are essential for healthy growth.
The tourist industry is an essential part of the Spanish economy.
vital extremely important and necessary, especially in order to avoid serious problems:
A vital piece of equipment on the spacecraft had stopped operating.
It is vital that the aid is sent immediately.
compulsory if something is compulsory, you must do it because of a rule or law:
Maths and Science are compulsory subjects.
All new staff undergo a compulsory training course.
obligatory if something is obligatory, you must do it because of a rule or law. Obligatory is more formal than compulsory:
The use of seatbelts is obligatory.
Safety regulations have made it obligatory for all competitors to wear fist protectors.
mandatory if something is mandatory, you must do it because it is the law. Mandatory is more formal than compulsory and sounds stronger:
School attendance is mandatory.
a prisoner serving a mandatory life sentence
requisite /ˈrekwəzət, ˈrekwɪzət/ formal [usually before noun] the requisite things are the ones that you need to have in order to do something:
The other candidates lacked the requisite skills.
the requisite evidence needed for a successful prosecution

[TahlilGaran] English Thesaurus ▲