I can’t think of any good reason for this word to be easy to read or easy to guess how to say. Or even suitably derived from its etymological roots. What would be the point of that? It’s not just that English spelling and pronunciation are like a bad relationship that has been allowed to get too tangled and to play too many perverse games for too long, grabbing bits from one place and applying rules from another place with the evident goal of keeping everything from being too easy – enforcing the idea that following a tangle of capricious and arbitrary rules is some sign of intellectual and moral superiority. It’s that this word in particular is an apposite instance for form to follow function.
Can you see what it is and where it comes from? Do you want any clues? OK: it’s three syllables. And the vowel at the heart of each syllable is what we (for anachronistic reasons, seldom explained or understood, that mess with the perception of millions of people) call “long.” And, of course, the ch is said as /k/.
Got it? Yeah, it’s from chaos (from Greek χάος, naming the primordial state of the universe, and also the state of the spoon-and-spatula drawer in my kitchen) plus ize as in Bette Davis (surely we all Bette-Davisize on occasion).
Of course the Greek pronunciation of χάος is just like the English pronunciation… if you only count the last sound in it, and don’t get too sticky about the specific articulation of /s/. The first consonant is different and so are the vowels, but that’s just because English merged the voiceless velar fricative with the stop, the long vowels changed during the Great Vowel Shift, and the short vowels shifted a bit except for where they didn’t. And then, when chaos and ize got mashed together and the s disappeared (about which more in a moment), the o also became “long” because there’s another vowel right after it and we just wouldn’t know what else to do there. Because while we’re all trying to follow and enforce weird rules to make sure we don’t look dumb (and other people do), we’re actually just guessing and making it up by analogy a lot of the time. When you sow the wind, you reap the whirlwind!
Anyway. About the form of this word. The usual way to make it, on the basis of Greek morphological derivation (which of course we all know, right?), the same thing that gave us chaotic rather than chaosic, would be chaotize. And that’s a word, and it means the same thing as chaoize. But I think we can all agree that chaoize is a much weirder, messier, more chaotic word (does it not K.O. your eyes?), and also it looks like Charlize (it’s right theron the page) and sort of like a weird spelling of chaise, which I can get onto as well. So we owe a little debt of thanks to Cyril Tourneur, author of The Transformed Metamorphosis (1600), who for his own reasons transformed and metamorphosized those roots into this version of the word, and whose book provides the sole citations for it in the Oxford English Dictionary.
I think we can all agree that a word meaning (again, quoting Oxford) “reduce to chaos or utter confusion” is quite handy, pretty much all the time but now more than ever. And I trust you can see why I prefer the version that’s more patently chaotic, capricious, unpredictable, and all those other things. Sometimes language change is like natural processes such as erosion and glaciation and sometimes it’s like letting kids loose in a sandbox, not just chaotic but chaoizing; why shouldn’t we have a word to name that that represents it?