(Note: This question is marginally related with this one.)

I am looking for a word to describe how obligatory something is. It may be mandatory, recommended or optional (given the context, more categories could apply).

The best options I have in mind are quite verbose:

These words reflect how binding/obligatory/mandatory a feature is.

These words reflect whether the feature is mandatory, recommended or optional.

I would like to use a single word that reflects that quality. A header that could cue in any of these values, if that's clearer. But I find these options jumping between awkward and plainly wrong:

These words reflect the bindingness of a feature.

These words reflect the obligatoriness of a feature.

Is there a simpler or more common word for this concept?

  • Requirements are mandatory/necessary by definition. Are you talking about features? And are you developing a formal specification or informal questionnaire?
    – TimR
    Jul 19, 2018 at 13:00
  • Sorry, commonly used lingo here. Features fits better.
    – guest_user
    Jul 19, 2018 at 13:04
  • 1
    I think it’s going to be difficult to find exactly the right word because optional/recommended/mandatory isn’t usually viewed as a continuous range of “obligatoriness”. You could have a range of how strongly something is recommended though.
    – ColleenV
    Jul 19, 2018 at 13:09
  • I guess semantics can be extended if properly defined (so is the case with MAY/SHOULD/MUST in the linked question), as long as the general meaning fits. A good word could be one that describes "obligatoriness" as the descriptor for "is the thing obligatory?" value, even if doesn't perfectly cover the other two values.
    – guest_user
    Jul 19, 2018 at 13:14
  • 1
    @Tᴚoɯɐuo yes, the use of "how mandatory something is" is inaccurate and that's why I am looking for a better word. But putting these adjectives (or concepts) in a scale makes enough sense to be part of a standard (and a standard that plays a crucial role for specifying networking technologies used all over the world, for that matter). Even if it is an arbitrary choice of scale, it is not a meaningless one ;)
    – guest_user
    Jul 19, 2018 at 14:14

5 Answers 5


Consider necessity and its adjective form, necessary.

necessity noun 1 (mass noun) The state or fact of being required. ‘the necessity of providing parental guidance’ - ODO

Your sample sentences would then be:

  • These words reflect how necessary a feature is.

  • These words reflect whether the feature is necessary.

  • These words reflect the necessity of a feature.

Note that the last example tends to default to a natural reading that the feature is necessary.


I suggest deonticity.

In linguistics the term deontic is used for words and constructions “expressing duty or obligation”, and although the nominalization deonticity is usually used to speak of the fact of such expression I see no reason why it should not be extended to speaking of the degree of duty or obligation expressed.

However, deontic and deonticity are fairly recondite terms which will not be understood by ‘lay’ readers; so depending on the context you might be happier with a longer phrase such as “degree of need”, or with a sideways jump to something like “desirability”.

  • But mandatory is binary, yes/no. It doesn't admit degree. We can't ask How mandatory is it? at least not logically.
    – TimR
    Jul 19, 2018 at 13:47
  • 3
    @Tᴚoɯɐuo W e l l . . . (1) Something may be mandatory in some circumstances but not others. (2) We're talking about the category, not the individual terms. The term "mandatory" may be said to express a maximal degree of deonticity, just as "prohibited" expresses a minimal degree of deonticity. Jul 19, 2018 at 13:57
  • I like the answer and think the definition hits exactly the nuance I was looking for. Unfortunately it is, as you remark, too esoteric for "layman" usage.
    – guest_user
    Jul 19, 2018 at 14:09

I've been looking for such an all encompassing term for the 'mandatory-ness' of something for a quite a while and had previously settled on the word 'Optionality', as I liked how the '-ality' suffix could convey the '-ness' property of the concept it was attached to.

But I believe I have now found a new favourite word to convey mandatory-ness; that word is Engagement. This fits well with the 3 levels of engagement suggested by the OP; i.e. mandatory engagement, recommended engagement, and optional engagement.


Informally, something like a software feature can be:

a "must have" feature
a "nice to have" feature
a "not needed" feature

Formally, a specification only needs to concern itself with "required features".

If you're writing a letter to someone indicating that a customer, say, has annotated a list of features:

The customer has annotated the attached list of features. Some are required, others are on their wish list, and some are unnecessary.

If you are advising someone about features you think they may need:

We have annotated the list of features based on our analysis of your needs. Some we have flagged as mandatory, others as optional but recommended, and some we have marked as unnecessary.

  • Unfortunately, explicitly listing the values is what I am trying to avoid, just because I am cuing it in: The words "must have", "nice to have" and "not needed" describe the <magic word> of the feature.
    – guest_user
    Jul 19, 2018 at 13:16
  • As remarked above by ColleenV, as this is not a continuous range of options, your quest for a single word is futile. Something which is on the wish list but not required is not "mandatory to some degree". Sounds to me like you're trying to name a column in a database or the property of a class. How would you name a column to describe the fact that its possible values were "Yes", "No", and "Maybe"?
    – TimR
    Jul 19, 2018 at 13:38

I'd suggest the word important or importance.

For example if something is important then it's mandatory and vice versa; if it's not so important, or unimportant, then it's optional.

A good thing about this word is that it's very common -- easily understood by a lay audience, basic vocabulary, and therefore natural-sounding and understood intuitively -- more so than other suggestions like deonticity or even engagement (which I don't understand in this context) or necessity.

It's also not a boolean or a binary word, i.e. there can be a sliding scale of importance (e.g. required, recommended, optional, ignored) -- perhaps unlike "necessity" where perhaps arguably something might be either needed or not.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .