I want to create a poster titled "An Incomplex Introduction to Complexity-based Cryptography." As you see, it contrasts the words incomplex and complexity. (Words like simple or easy do not provide this.) I looked up the word incomplex, and found it in a few dictionaries:

However, most dictionaries do not include this word. Is it a legitimate word at all? Can I use it?

  • 4
    That sounds like a perfectly cromulent word. Commented Dec 21, 2010 at 13:47
  • 1
    @Joshua: Ironically, the word cromulent itself isn't listed in ordinary dictionaries :) I found its meaning here: en.wiktionary.org/wiki/cromulent. Commented Dec 21, 2010 at 17:45
  • 2
    @SadeqDousti That's probably why he used it :)
    – Stan
    Commented Mar 2, 2014 at 22:27
  • "incomplex" must be something about "income", right?
    – GEdgar
    Commented May 2, 2018 at 0:21
  • @GEdgar - Yeah, it's income from multiple sources.
    – Hot Licks
    Commented May 2, 2018 at 0:47

8 Answers 8


It's definitely not a standard English term, and as such will likely sound wrong to most people, even if it is shown somehow to be a legitimate term.

I understand your interest in using it to contrast against "complexity" but I think you would find that "simple" would work just as well, as simple is quite commonly used as the opposite of complex. And you'd get far fewer people wondering if it were a real word.

If I were trying to write the title, I'd probably go with, "A Simplicity-based Introduction to Complexity-based Cryptography." Snappy, and you have full part-of-speech agreement between your contrasting phrases--which makes it crystal clear that you're going for a fun contrast.

  • simplicity and complexity are not symmetrical as applied in the sentence. Complexity is to complex and simplicity is to simple, yes.
    – Lambie
    Commented May 4, 2018 at 13:53

If it's for a title you can do whatever you want, especially if you are coining a word for use in a knowledge domain.

But you will be better understood if you use a word like simple instead of incomplex. Trust me when I tell you that simple does provide a specific contrast to complex.

If you can't abide simple, I'd suggest you try non-complex instead of incomplex.


Consider using the word "uncomplicated" making your title

An Uncomplicated Introduction to Complexity-based Cryptography

I suspect you were attempting to create a parallel between "incomplex" and "complexity-based"

"Uncomplicated" will get closer to that goal than "simple" (though the contrast between "simple" and complexity is arguably more powerful)

  • If you can justify it, it might be. Can you justify it or not, please? Commented May 3, 2018 at 22:21

I checked in Oxford English Dictionary 2nd Ed. (OED 2nd Ed.), and interestingly the word "incomplex" was coined in early 17C and last usage was recorded as late as 19C. It is defined as :

Not complex; not complicated or involved; simple.

Although I could not find in other dictionaries, I support your title as it's the legal usage of prefix in-.


Since your proposed incomplex is clearly in a gray zone, I will suggest that you use, instead, a word which is solidly in most dictionaries, as far as I can tell:


(sometimes spelled non-complex)

For example, Oxford says:

Easy to analyse or understand; simple. ‘a single, non-complex idea’

Your title would then be

A Noncomplex Introduction to Complexity-based Cryptography

which I think preserves the catchiness of your original.


There are only two references with usage of the word, incomplex, cited on Stanford Encyclopedia of Philosophy. One is from William of Ockham (1287-1347) with his explanation of the differences between intuitive and abstractive cognition. The other is from Adam de Wodeham (1295–1358) on the same topic, in his Lectura Secunda (which apparently he learned from Duns Scotus (1266-1308)). So it was familiar to Medieval philosophers and theologians.

Incomplex is (or should be) familiar to at least a few philosophers. Quoting from Phases of Thought in England, by Meyrick H. Carré (c.1949, p.157), who first quoted Ockham's work in the original Latin:

Intellectus nullum propositionem potest formare nec per consequens apprehendere, nisi primo intelligat singularia, id est incomplexa.

Then proceeded to make his own use of the word:

Incomplex abstract knowledge furnishes us with immediate and necessary judgements...

Gottfried Wilhelm Leibnitz, in Human Understanding (c.1896, pages 21, 237, and 398), was very familiar with the term:

...what the logicians call an incomplex term...

Cause is that which produces a simple or incomplex idea; effect is that which is produced.

...certain logicians of the Reformation who were in some measure of the party of the Ramists, were not wrong in saying that the topics or orders of invention...serve as much for the explication or very detailed description of an incomplex theme, i.e. of a thing or idea, as for the proof of a complex theme, i.e. of a thesis, proposition, or truth.

And there are numerous independent references to the word, including the 1913 edition of The Oxford English Dictionary, vol. 5 (H-K), p. 166 (along with Roget's Thesaurus and many more dictionaries).


An Outline Of Modern Knowledge, by F. Aveling (c.1932, p.332) [9]

Primitive and incomplex wholes become more complex and fully structured...

Basic Writings of Saint Thomas Aquinas, vol. 2, Edited by Anton C. Pegis (c.1945, p.1054)

Under the first head there are ten points of inquiry: (1) Whether the object of faith is the First Truth? (2) Whether the object of faith is something complex or incomplex, i.e., whether it is a thing or a proposition?

Although I found plenty of references for incomplex, some might seem too obscure and dull for most readers. So I've attempted to round up a few instances in literature:

The Mistress of the Ranch, a Novel, by Frederick Thickstun Clark (c.1897, p.16)

Sam turned his full face upon her. It was a face capable of only one expression at a time, and that of some big, incomplex emotion.

The Strangers' Banquet, by Donn Byrne (c.1919, p.180)

He was too incomplex to worry about styles for men or what suited him.

In Main Currents in Nineteenth Century Literature, by Georg Morris Cohen Brandes (c.1906, p.295), speaking of Théophile Gautier:

...when (as in "Le premier rayon de mai") he reproduces the simple, almost sensual, at any rate perfectly incomplex, feeling of happiness produced by the close vicinity of the beloved one.

The Country Parson and Albert Savaron, by Honoré de Balzac (c.1897, p.152)

Who is there with a thinking brain or a wounded heart that can pass through a forest and find the forest dumb? Before you are aware its voice is in your ears, a soothing or an awful voice, but more often soothing than awful. And if you were to examine very closely into the causes of this sensation, this solemn, incomplex, subduing, and mysterious forest-influence that comes over you, perhaps you will find its source in the sublime and subtle effect of the presence of so many creatures all obedient to their destinies, immovable in submission.

So many great writers and thinkers have produced fine literature and ideas with the term, incomplex, that it seems a pity not to easily recognize its meaning and perhaps even to keep it alive with modern usage.

  • "An Incomplex Introduction to Complexity-based Cryptography."

...is an elegantly phrased, creative, and clever title. It's a mouthful, but I like it. Oh, and to answer the question specifically:

  • Yes, incomplex is a legitimate word.
  • Yes, anyone should feel free to use it whenever they like (in context, of course).
  • At least you've given usages later than the OED's 1827 example, which is the latest usage it gives; the OED's entry for the word hasn't been updated since the 1900 edition. In other words, the OED entry you link to is the same as the entry that appears for the word in both the 1989 hard copy and the constantly udated online OED. Anyway, it's a word is the answer. Great answer. +250 Commented May 4, 2018 at 21:21
  • It was a wonderful opportunity to learn something interesting, thank you so much.
    – Bread
    Commented May 4, 2018 at 21:31

Reading the 1897 book "My Life in Christ" by the Russian Orthodox priest St. John of Kronstadt, I came across this term frequently (on the pdf I found later I counted use of 46x).

  • 1
    Hello, Ron. The accepted answer's 'It's definitely not a standard English term, and as such will likely sound wrong to most people, even if it is shown somehow to be a legitimate term' is of far more value to people contemplating using the term in almost every conceivable circumstance. The odd example of a usage is not a telling argument for its acceptability. / This would be better given as a 'comment'. But, as everyone here has needed to, you need to get to 50 rep points before you can do that. Commented May 1, 2018 at 16:42

A Gentle Introduction to Complexity-based Cryptography.

This is the canonical English expression for such a title.

  • 5
    Oh? In which canon?
    – user867
    Commented Apr 13, 2015 at 6:57
  • @user867 Modern English.
    – aaa90210
    Commented Apr 13, 2015 at 7:01
  • 2
    Can you provide a reference of some sort for that, I mean.
    – user867
    Commented Apr 13, 2015 at 7:22

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