I have a question about this. Isn’t this the same as “to become sick”?
I guess there are other ways to say this, such as “to get sick”, assuming that that’s what “to fall ill” means since that is kind of different than “to be sick”, which is when you’re already sick.
That’s the thing, “to be sick” is being sick now.
But “to fall ill” is also in the options for this word, which sounds like it’s the action of it happening now or in the future, isnt that the same as “to become sick”?
With that particular definition, it’s the beginning of being sick, however you want to say that in English. It’s not the state of continuing to be sick after the beginning.
There are some other definitions for 病む too.
From here
1 病気になる。わずらう。「久しく―・んでいる」
2 傷などが痛む。
「私も、何様なに―・んだろうと思ってね」〈小杉天外・魔風恋風〉
3 病気におかされる。「胸を―・む」「リューマチを―・む」
4 心をなやます。心配する。「ささいなことを気に―・む」
For what it’s worth, all of the example sentences in my dictionary that relate to a person currently being sick use ~ている. For example:
彼女は心臓を病んでいる。She is troubled with heart disease.
Sometimes in Japanese you’ll see a present condition being described as the past tense of a verb that’s about becoming that condition, e.g., 疲れた (I became tired) for “I am tired”. But in this case it looks like the present condition is formed as continuous, i.e., ~ている. I’d guess that the present tense (病みます、病む) is the “becoming” sense, as in 病気になる.
All guesses though, hopefully someone will have a more authoritative response.
Or it may be possible that the conception of “getting sick” as not quite yet being actually sick is culturally and linguistically specific, in which case there’d be no direct translation. In other words, maybe they’re thinking of sickness as a continuum, whereas we think of “being sick” as a discrete moment with a separate on-ramp.