Difference between Mandatory and Indispensable

Key Difference: Mandatory means something that has been handed down in a mandate or has been commanded. Indispensable means something that is important and cannot be ignored or is necessary. Mandatory is backed by laws or some type of rules, but indispensable is something that’s subjective and not required by rules or laws.

Mandatory and indispensable are words that are commonly confused and assumed to be interchangeable because of their similar definitions, but while these words might have a similar definition, they are used in different contexts and are not interchangeable.

These two words are commonly found in history and literature as well are used by news readers when talking about laws and policies. And the ways that they are used often result in the surrounding confusion, but there is a pretty easy way to differentiate the two. Let’s take a look at them separately.

The word ‘mandatory’ means something that has been handed down in a mandate or has been commanded. Mandatory refers to something that has been set by the laws, which means not following it would be subject to consequences. It is something that is forced such as it is mandatory to hold a license before you can drive. Not holding a license can result in fines as well as punishment. It can also refer to a something that is compulsory such as certain courses are mandatory in first year to pass on to the second one. While it is not a law, it is commanded by the rules set by the university and comes with certain consequences if not followed.

While, ‘indispensable’ means something that is important and cannot be ignored or is necessary. It is not backed by law. The similar word refers to something that is essential and necessary but discarding it does not offer any consequences. It is used commonly to describe the important of something such as a situation, objective or person. For example, medical certificates are indispensable documents which means they are extremely important but if someone throws them out they are not punished. Another example when it comes to a person is, Tom was an indispensable part of the testing team.

There are a few things that make the two words start apart, one is that mandatory is backed by laws or some type of rules, but indispensable is something that subjective and not required by rules or laws. Also, mandatory means it is objective and required by everyone while indispensable is subjective which means what is important for one person doesn’t have to be by another person.

Comparison between Mandatory and Indispensable:

	Mandatory	Indispensable
Definition	This refers to something that is required by law and cannot be disregarded or modified	Something that is necessary and cannot be neglected
Etymology	Late-15th century: from Latin mandatum ‘something commanded’.	mid-16th centuryfrom medieval Latin ‘indispensabilis’
Type	Objective – same for all	Subjective – not same for everyone
Type of Figure of Speech	Adjective	Adjective
Synonym	compulsory, forced, imperative, incumbent, involuntary, necessary, nonelective, obligatory, peremptory, required	all-important, critical, essential, imperative, integral, must-have, necessary, necessitous, needed, needful, required, requisite, vital
Antonym	elective, optional, voluntary	dispensable, inessential, needless, nonessential, unessential, unnecessary, unneeded
Examples	These courses are mandatory for the first years. It is mandatory to have a license to practice medicine.	Sam was an indispensable assistant to the CEO. This book was indispensable for his thesis project. The volunteers' help was indispensable.

Reference: Cambridge Dictionary (Mandatory, Indispensable), Merriam-Webster (Mandatory,
Indispensable), Collins Dictionary - Indispensable, Dictionary.com – Mandatory, Stack Exchange
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