Interesting etymologies/relations of WK vocabulary

While slowly going through my burn reviews I noticed that some words that used to give me issues are in fact extremely easy to memorize if you know a bit more about Japanese grammar and vocabulary, and as such I thought it would be interesting to catalogue these things here, hoping that it may help somebody else.


I just burned this entry today and it’s what motivated me to make this post, because I remember that it gave me trouble at first but reviewing it today I realized that it’s in fact absolutely obvious what the word means.

The trick that I ignored back then is that is a formal/old school version of ない that in modern days is mostly used in set expressions and constructions, but as such 思わず is effectively 思わない which is just the regular negative form of 思う (to think).

So 思わず is literally “not thinking”, hence “unconsciously” or “involuntarily”.

Interestingly the antonym 態と (on purpose, deliberately) can also be decomposed as わざ + と where わざ can be written as or 業, the former being taught on WK with this exact same reading. と is just と, the particle which I presume in this case just means “with”, as in “with an act of intent”.

Unfortunately I find this less helpful because while 技(わざ) apparently used to mean “an act of intent”, in modern Japanese it came to mean “skill” or “technique” which is sort of related but still a bit of a stretch to use as a mnemonic IMO. Still can be helpful to remember that the readings of 態と and 技 are the same and it’s not a coincidence.


This is another one featuring our friend the ず auxiliary. This one is a bit less straightforward than 思わず however:

So you start with (かり)meaning temporary. Then you make 仮なる(かりなる) or “to become temporary”. Then you put it in the negative, 仮ならない(かりならない)or “not to become temporary”, then you use ず intead of ない, giving 仮ならず(かりならず).

Then you’re lazy, and you drop the り to only keep a string of rhyming あ vowels like the Japanese like so much, giving かならず. Then you pick a kanji with the same semantics to write it and you have 必ず, meaning “always” or “without fail” (because it’s “not temporary”).


ず once more: 知らず is just 知らない (not knowing), so if someone is 恥知らず they are “not knowing shame”, they are shameless.


This one is a lot more obvious but I just got it during a review as well: あわせる is simply the regular causative form of あう. So since あう means “to meet” or “to join” (and a billion other things, admittedly) then this is “to make meet” or “to make join” or, in better English, “to join together” or “to unite”.

There are a bunch of other examples of verb conjugations used as stand-alone vocab, sometimes even using a different kanji, I’ll add them when I can think of them.

効く and 利く

This one is also very straightforward but it always bums me a bit that WK doesn’t point out these obvious relations: 利く(きく), taught on level 11 with the meaning “to work well” and 効く(きく) taught on level 25 with the meaning “to be effective”… are just alternate spelling for the same word. This is just a stylistic nuance in writing. It really feels like a wasted opportunity for WK not to point that out, instead preferring more dumb English-based mnemonics.

I’ll try to complete this list when I encounter more interesting words.

Please contribute your own finds!


This isn’t accurate. It’s not necessarily formal or old school. Maybe ぬ is but not ず. It’s also not just used in set expressions or constructions. People use it very often in every day spoken Japanese wherever appropriate.

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I was under the impression that it was mostly used in set expressions like 〜ずに (without doing something) or in constructions that sort of became their own vocab like 構わず, 思わず and the like. Is this not accurate?

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Nice idea. I’ve also been trying to use etymologies – both real and sometimes just made-up ones if I can’t find the real one – to try to help with memorization.

Ah, nice one! Makes sense. All those little individual steps. :smiley:

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I don’t remember where I picked this up, but I’m pretty sure that ~ず means something more like ‘without (doing X)’, so it is more similar to ~ないで than just ~ない.

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My understanding is that this is a relatively recent development because ず was no longer used as generic negation like ない, so now you can use ず with the に part implied, so indeed you have an “instrumental”/adverbial aspect.

Wiktionary says this:

From Old Japanese. Generally considered to be a combination of negation suffix ぬ (nu) in its 連用形 (ren’yōkei, “continuative or stem form”) of に (ni) + honorific suffix す (su).[1][2][3]

/nisu/ → */nzu/ → /zu/

Appears both as zu and as the older nisu form in the Man’yōshū poetry anthology.

I also found this stackexchange discussion that confirms what you say:

In the modern form, ず is only used as an adverbial (食べずに出る leave without eating). ぬ can replace ない.

So basically historically you could use ず much like ぬ and ない (the stackexchange has more details/subtleties) but nowadays ず is mostly only used productively as ず(に) with behaves roughly like ないで. At least that’s my understanding.

So you’re absolutely correct @Vanilla that in my examples in the original post the usage of ず is not particularly old-school since 思わず and 必ず are both just adverbs, so my description is a bit misleading.

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Ah. Here’s one that drove me nuts until I finally figured out the whole ~ず thing:


The WK mnemonic uses the kanji meanings directly, so it says “A mutual change you make with other people will go so smoothly that it will seem like everything is working as usual. It will be like everything is the same as it was before because the change was mutual.” But ‘mutual change’ on its own seems to indicate that ‘both of us are changing incompatibly’!

So, here the relation is that 変わる (かわる) means ‘to be changed’ or ‘to be altered’. Thus the negation of that would be かわらない, and the ‘without doing X’ version would be かわらず, ‘without being changed’, or ‘without being altered’.

Next, we can notice that the prefix 相~ (あい~) is a standard construction in Japanese to mean ‘together; mutually; fellow​’.

So, it’s literally the opposite of the WK mnemonic! It means ‘mutually without change’, or, in other words, ‘as usual’ or ‘the same’.


Oh I love this, I encounter this word regularly and I always have to look it up and it won’t stick, and yeah the WK mnemonic is too obtuse to be useful.

Oooh, you just made it click for me that this あい is the same as 合い. 相手 is “合い手”. Mind blown.


I guess I hadnt considered that a set expression. Even doing so, it’s hard to say since it’s so common as ず alone.

Im not sure if it’s taught this way in textbooks, but ず on its own can be more like ないで on its own as well without the に. It’s often absent, even in literature. Like you mentioned, theres plenty of words that can be considered their own vocab like とりあえず, but even excluding those it’s hard to say whats more common.


Yeah you’re absolutely right, I overcomplicated things in my attempt to simplify them. I took a deep google dive in the history of negation in Japanese the other day and it tainted my approach here.

Still, an interesting discussion as a result!


得る and 獲物

The reading for 獲物(えもの) meaning pray/spoils/trophy comes from 獲る(える) meaning to gain or to acquire which is much more commonly written with a different kanji: 得る, as taught on WK level 19.

Interestingly and confusingly, while える can be spelled 得る or 獲る without change of meaning according to jisho, えもの can also be spelled 獲物 or 得物 but here the meanings are different: while 獲物 means prey/spoil/trophy, 得物 means “(hand) weapon​” or an archaic term meaning “one’s forte; one’s special skill; weapon one is skilled in using​”.

得物 is also apparently not a very common term, unlike 獲物.



There’s a very obvious relation that I only now noticed: 済む (to finish, to be completed) is the root of the very common interjection すみません (sometimes すまない) meaning of course “excuse me”.

According to wiktionary the original meaning was something like “(the trouble) is not settled”, hence its use for apologizing/showing gratitude.



This means “to fall into” and is effectively a respelling of 落ち入る.


If you want to get super old school and formal:

居候 - いそうろう

the characters 候 had a very significant role all the way up till recent history, and the reading そうろう was actually quite common in the past. This character was often used in this way in epistolary (候文) contexts or official documents as a formal way of saying である, ます, or です. You can also use it in a similar way; で候, で御座候, に候. Thus the word 居候 just means something similar to “to (simply) exist (in someone else’s house)”, or in modern context; a freeloader.

Now that you know this, here are some trivially easy examples using 候:



一寸参堂仕り度 候えども、大兄の消極主義に反して、出来得る限り積極的方針を以て、此千古未曾有 の新年を迎うる計画故、毎日毎日目の廻る程の多忙、御推察願上候。

These sentences don’t even use any of those pesky hirigana or katakana words and allow you to almost completely rely on kanji! Perfect for those people who decide to start reading after a few levels of Wanikani but are thrown off by the sheer amount of non-kanji words in よつばと for example.


There’s also an additional archaic negative i.e. ざる which is very common in older contexts.



Yes, that’s why the Three Wise Monkeys are monkeys - みざる see-no-evil, きかざる hear-no-evil, いわざる speak-no-evil, they’re also homophones for 見(ない)猿 the un-seeing monkey, 聞か(ない)猿 the un-hearing monkey, 言わ(ない)猿 the un-speaking monkey.

They’re sometimes accompanied by a fourth monkey, せざる do-no-evil.


Honestly this blew my mind. This is such a cool etymology!