I already knew the adjective 清潔 that means "clean, hygienic", but I recently came across the word 衛生的 which also means "hygienic" and I don't understand in what situations should I use each of them.

So far, I've come across an entry in HiNative that states that

衛生 is a noun while 清潔 is a Na-adjective.

which makes me think that the adjectivized form 衛生的 must be really close to 清潔 because the only difference they point out is grammatical, but not in terms of meaning.

I've also made a Google Image search to understand the concepts, and it looks like 清潔 returns images related to "cleaning" in general (such as 掃除) while 衛生 returns more "sanitizing" images so to speak, but I think that I'm hitting many pages in the Chinese usage of 衛生 so I am not so sure this is the actual difference between both terms in Japanese.

Also note that this answer suggests that 清潔

清潔 is being free from dirt, dust, blot, bacteria, etc.

So I can see how 清潔 could mean hygienic in a sanitary sense as well.

Finally, looking at their 漢字 spelling

衛生: 衛 defense, protection + 生 life

清潔: 清 pure, purify, cleanse + 潔 undefiled, unsullied, pure

reinforces the idea that 衛生, i.e. "protecting life", is closer to "sanitized" in a medical sense, as opposed to just 清潔, i.e. "clean" or "pure", but it's just my speculation.

All in all, I figured out the difference is that 衛生 is more for clean as in "not dirty", whereas 衛生 is closer to "sanitized" as in "without pathogens, bacteria, viruses, etc." but I'm not sure about this conclusion and I still don't know how to use these terms. Can you explain in what situations should I use each word, please?

1 Answer 1


衛生 is more about the concept of hygiene. 衛生的 mostly means in terms of hygiene and normally does not replace 清潔だ.

清潔 usually means physical bacteria-freeness.

  • 部屋を清潔に保つ keep the room clean
  • 部屋を衛生的に保つ

The latter may be passable, but is at least less idiomatic than the former.

  • 清潔な手 clean hands
  • ??衛生的な手

The latter is hardly possible. On the other hand, 清潔な食器 would be dishes that are clean now; 衛生的な食器 means bacteria-proof(?), with some coating, for example. That is, 衛生的な食器 does not talk about whether or not it's clean now rather about the way it is made.

衛生的 is more often used as in 衛生的によくない (bad in terms of hygiene).

  • 外から帰ってきて手を洗わないのは衛生的によくない
  • (Literally) not washing your hands when coming home from outside is not good in terms of hygiene.
  • 1
    Just to confirm, the usual word for something being clean or even sanitized would then be 清潔, whereas 衛生的 has more to do about the nature of the object than the state of being clean/dirty?
    – jarmanso7
    Mar 13, 2023 at 14:31
  • 1
    I can't help but parse your last point as "in terms of 衛生", just as 政治的に is "in terms of politics" or 個人的に is "in my personal opinion" i.e. as a construction made out of Noun + 的に. therefore it really doesn't help me understand how 衛生的 works an adjective itself, i.e. how it works when qualifying a noun via the な copula. I hope I made sense.
    – jarmanso7
    Mar 13, 2023 at 14:35
  • So, for example 清潔な道具 would be a clean tool, but 衛生的な道具 would be a tool used to sanitize or clean something else?
    – jarmanso7
    Mar 13, 2023 at 14:40
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    @jarmanso7 If you want to say clean, yes, you can stick to 清潔 or きれい. Re 的, you are right but just like political (and probably hygienic) works predicatively (he's political), 衛生的 can mean with high awareness about hygiene. Re last point, to an extent, it's a matter of collocation and 衛生的なX is not usually idiomatic. That said, 衛生的な道具 would sound tools for which special treatment is applied to keep it clean (like medical equipment).
    – sundowner
    Mar 14, 2023 at 1:33

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