When is 事業 read as じぎょう and when as ことわざ


I came across the following sentence from the _Dictionary of Japanese Grammar_
series:

> Ｘ氏は、一方で慈善事業をやりながら、他方でかなりあくどい商売をしているという噂だ。

I think `慈善事業` should be read as `じぜんじぎょう`. But as I look up the dictionary
for confirmation, I noticed `事業` can also be read in _kunyomi_ , i.e. `ことわざ`,
where one of its definitions `仕事・じぎょう` also matches with the context in the
sentence. My questions are:

  * When should the _onyomi_ and _kunyomi_ of `事業` be used?

  * Moreover, shouldn't `ことわざ` mean 'proverb'? Does that mean `ことわざ` is polysemous?




I'd like to add onto
[samhana](https://japanese.stackexchange.com/users/42257/samhana)'s answer.

### Background about the term and reading

The ことわざ reading for 事業 is valid, but it is also ancient. This reading is not
used in modern Japanese.

  * The ancient ことわざ reading is attested in a text from 757, as indicated in Shogakukan's _Kokugo Dai Jiten_ entry [here](https://kotobank.jp/word/%E4%BA%8B%E6%A5%AD-503337#E7.B2.BE.E9.81.B8.E7.89.88.20.E6.97.A5.E6.9C.AC.E5.9B.BD.E8.AA.9E.E5.A4.A7.E8.BE.9E.E5.85.B8).  
_(After a site redesign a while back, Kotobank's formatting makes it really
hard to read the entries. The top paragraph under the bold heading, the first
〘名〙 section, is for the ことわざ reading.)_

  * This reading is a simple compound of 事【こと】 "abstract thing, fact" + 業【わざ】 "intentional action": doing something intentionally and with purpose. The meaning is thus roughly the same as modern 事業【じぎょう】.
  * This is cognate with 諺【ことわざ】 from 言【こと】 "word" + 技【わざ】 "technique, skill", but it uses different senses of the underlying roots.
  * Considering that multiple dictionaries still list this reading (which usually doesn't happen for Old Japanese-only terms), I suspect that 事業【ことわざ】 may be used some in Classical Japanese as well. In fact, looking at it now, I see that the entry in my local copy of Daijirin includes a quote from the [養生訓【ようじょうくん】](https://ja.wikipedia.org/wiki/%E9%A4%8A%E7%94%9F%E8%A8%93), a text from 1712.
  * At the same time, I also don't see any pitch accent information for this reading, which usually indicates that the dictionary compilers don't consider this to be used in modern mainstream Japanese (a.k.a. 標準語【ひょうじゅんご】).

### The questions

Back to your questions:

> When should the _on'yomi_ and _kun'yomi_ of 事業 be used?

In modern writing and speech, only use the _on'yomi_ of じぎょう.

If you're writing something deliberately archaic, using Classical Japanese,
you might be able to use the ことわざ reading. However, expect that modern readers
will need ruby ([振り仮名]【ふりがな】) to understand that you intend this reading.
Also, make sure you do a lot of research into how this term was used to make
sure you understand it well enough to use it. (I certainly wouldn't be
comfortable myself trying to use this.)

> Moreover, shouldn't ことわざ mean 'proverb'? Does that mean ことわざ is polysemous?

Strictly speaking, ことわざ as a spoken word is indeed polysemous (at least, in
older Japanese; see also [the Japanese Wiktionary entry for
ことわざ](https://ja.wiktionary.org/wiki/%E3%81%93%E3%81%A8%E3%82%8F%E3%81%96) for
even more homophones of different meanings, a.k.a. 同音異義語【どうおんいぎご】) -- but the
kanji spelling 事業 is less ambiguous, and would never mean 諺.




I'd like to add onto
[samhana](https://japanese.stackexchange.com/users/42257/samhana)'s answer.

### Background about the term and reading

The ことわざ reading for 事業 is valid, but it is also ancient. This reading is not
used in modern Japanese.

  * The ancient ことわざ reading is attested in a text from 757, as indicated in Shogakukan's _Kokugo Dai Jiten_ entry [here](https://kotobank.jp/word/%E4%BA%8B%E6%A5%AD-503337#E7.B2.BE.E9.81.B8.E7.89.88.20.E6.97.A5.E6.9C.AC.E5.9B.BD.E8.AA.9E.E5.A4.A7.E8.BE.9E.E5.85.B8).  
_(After a site redesign a while back, Kotobank's formatting makes it really
hard to read the entries. The top paragraph under the bold heading, the first
〘名〙 section, is for the ことわざ reading.)_

  * This reading is a simple compound of 事【こと】 "abstract thing, fact" + 業【わざ】 "intentional action": doing something intentionally and with purpose. The meaning is thus roughly the same as modern 事業【じぎょう】.
  * This is cognate with 諺【ことわざ】 from 言【こと】 "word" + 技【わざ】 "technique, skill", but it uses different senses of the underlying roots.
  * Considering that multiple dictionaries still list this reading (which usually doesn't happen for Old Japanese-only terms), I suspect that 事業【ことわざ】 may be used some in Classical Japanese as well. In fact, looking at it now, I see that the entry in my local copy of Daijirin includes a quote from the [養生訓【ようじょうくん】](https://ja.wikipedia.org/wiki/%E9%A4%8A%E7%94%9F%E8%A8%93), a text from 1712.
  * At the same time, I also don't see any pitch accent information for this reading, which usually indicates that the dictionary compilers don't consider this to be used in modern mainstream Japanese (a.k.a. 標準語【ひょうじゅんご】).

### The questions

Back to your questions:

> When should the _on'yomi_ and _kun'yomi_ of 事業 be used?

In modern writing and speech, only use the _on'yomi_ of じぎょう.

If you're writing something deliberately archaic, using Classical Japanese,
you might be able to use the ことわざ reading. However, expect that modern readers
will need ruby ([振り仮名]【ふりがな】) to understand that you intend this reading.
Also, make sure you do a lot of research into how this term was used to make
sure you understand it well enough to use it. (I certainly wouldn't be
comfortable myself trying to use this.)

> Moreover, shouldn't ことわざ mean 'proverb'? Does that mean ことわざ is polysemous?

Strictly speaking, ことわざ as a spoken word is indeed polysemous (at least, in
older Japanese; see also [the Japanese Wiktionary entry for
ことわざ](https://ja.wiktionary.org/wiki/%E3%81%93%E3%81%A8%E3%82%8F%E3%81%96) for
even more homophones of different meanings, a.k.a. 同音異義語【どうおんいぎご】) -- but the
kanji spelling 事業 is less ambiguous, and would never mean 諺.

