I am looking for a word that describes the exact opposite of identity.

I have this sentence that says The identity operator returns true if the operands are strictly equal.

In other terms is there a word for not strictly equal / strictly unequal?

There is an operator that does the opposite: The opposite word operator returns true if the operands are strictly unequal.

I tried to google the antonyms and such, but none of the proposed words match or satisfy this case in my opinion. Or did you see or do you think one them could be used?

  • difference
  • dissimilarity
  • opposite
  • non-identity
  • other suggestions?

Definitions for this case:

equal - only very few characteristics cannot be in common.

strictly equal - all characteristics are in common.

unequal - only very few characteristics can be in common.

not strictly equal - none of the characteristics are in common.

I don't want it to be a Math question. They use symbols not words.

  • 4
    This is surely a maths-specific usage, not relevant to other English, and would be better asked on Maths SE. – Edwin Ashworth Jul 24 '15 at 7:51
  • What is the difference between unequal and strictly unequal? – Vladimir Kornea Jul 24 '15 at 7:57
  • @vladkornea In some computer languages, it possible that a comparison of two variable of different types will yield equality. A "strict" comparison won't yield equality unless the two variables are of the same type. So strict equality implies equality, but not vice versa. – deadrat Jul 24 '15 at 8:12
  • I want it to be more general @deadrat - I do not want to restrict the creativity of the users. Please see definitions in updated question. The example sentence is merely an example. Sorry for the misunderstanding. – Ely Jul 24 '15 at 8:22
  • @Elyasin You defined the term as "none of the characteristics are in common". This is different from "not identical". Can you clarify which you mean? – Vladimir Kornea Jul 24 '15 at 8:41

As a coder, when I think of an "identity operator" I put it into coding terms where there might, for example, be an associated truth table that identifies how it is evaluated.

and, in most coding languages, there is a Negation operator that can be combined with it to show indicate the opposite usage. The obvious example in most languages being equal "=" versus Not equal "!=". where the exclamation point indicates that the associated truth table for this expression must the opposite.

I'm not sure I've ever seen a single operator that implies "NOT identity", so if you have created one - congratulations! you get to name it.

Hmmm.... the disparity operator?

And at that, I sure wouldn't want to have to have the debate on exactly what percentage of characteristics have to differ before you flip from equal to unequal. And are the characteristics weighted as to their importance in determining when something ceases to be equal? Writing precise definitions without precise meanings (exactly how many is "a few"?) is a tough thing to do!

  • The definitions in the OP kind of fail, but disparity is precise, in that it covers there being two objects (true) or there being one object and null (true). I suggest plurality because it is descriptive of the state of having two equal objects with disparate identities, but disparity covers that and having one object with nothing. So +1 dispite throwing plurality out there as well. – stevesliva Jul 25 '15 at 4:42
  • Not easy to digest, but I think your word choice is the most appropriate in my opinion. Thanks. – Ely Jul 27 '15 at 6:45

Non-identity/strict not equal: The non-identity operator returns true if the operands are not equal and/or not of the same type.


The first word that comes to mind is inequality operator. Wikipedia makes a distinction between equality and inequality; the question is if there is any real difference between your identity and the concept of equality.

Microsoft calls the != operator the inequality operator, and it seems to do what you describe.

(I would rephrase "strictly unequal" to "not strictly equal" to indicate the exact opposite behaviour, by the way.)

  • Thank you @oerkelens - I updated my question with more details. Sorry having been so imprecise. – Ely Jul 24 '15 at 8:23
  • It is more analogous to the ! operator, the not operator since it is the opposite of identity, so !value. – Jordan Jelinek Jul 20 '17 at 19:56

As the terms are commonly used in most programming languages, "equal" means that the observable values of the two entities being compared are identical. "Strictly equal" means that the two entities are, in fact, the same entity, but presumably reached using two different pointer/reference variables.

Your definitions don't make any sense.


The difference operator returns true if and only if the operands are not strictly equal.

  • can you let me know where i can read upon this? any reference? is it established usage? – Ely Jul 24 '15 at 8:24
  • I thought you knew the semantics and just needed a name. PHP calls the operator "not identical" for non-arrays and "non-identity" for arrays. Check php.net for details. – deadrat Jul 24 '15 at 8:35
  • Most people interpret "difference operator" to be -, the subtraction operator. – Hot Licks Jul 24 '15 at 12:23
  • @HotLicks Really? I've never heard or read anything in which subtraction was referred to as "a difference operator." If this is indeed about a comparison operator in a programming language, I would think that the fact that subtraction isn't commutative would make that unlikely. But maybe it's just me. – deadrat Jul 24 '15 at 15:21
  • @deadrat - "difference" is sort of like "quotient" and "remainder" which are the results of division and modulus operations. I also, like HotLicks, think of it as being a scalar value and not a boolean. – stevesliva Jul 25 '15 at 4:28

I don't think there is an established word for it, but maybe you could create one. Two points on the Earth's surface are antipodal if they are as far away as possible. So you could call this the antipodal operator.

  • That's what I was hoping. You're being creative. Thanks. Will think about it. – Ely Jul 24 '15 at 10:53

There is no such thing as "opposite" of identity. Whether two entities are identical is a true or false question. If they are identical, then all their properties are the same. Otherwise, at least one of their properties is different. However, you are not looking for this mere negation (non-identity), but for the far more exotic meaning of "not even one of their properties is the same". Let's call it anti-identity.

Entities in general can have countless properties. For instance, is a dog anti-identical to a keyboard? Both are physical entities, so that is one property which they do have in common, so they are not anti-identical. This sort of consideration makes this concept meaningless, except in narrow contexts like software. In that context variables have countable properties such as "value" and "type", and you could go through all of them and make sure that every single one of them is different. Here the concept can be made meaningful, but it would be useless, because it answers a question which it is never useful to ask.


You could call it a plurality operator, in the sense that it returns true if you have a plurality of objects in the comparison.


The state of being plural [more than one]

(Definitions of plurality and plural from here combined).

This is an English answer despite alluding to "objects" and return values. The OP's definitions of equal/strictly equal/etc make no logical sense to me in any context, but an opposite of the state of having one identity is the state of being plural. However the state of not being complicates the idea of calling plurality a true antonym of identity, which is why disparity, as suggested in another answer, is perhaps more precise.

But if you want to focus on there being multiple instances of perhaps equally-valued objects, plurality may be what you're looking for.


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