GG5, etc. etc.

I don't think those proposed changes helped much, in fact having both "to become ill" and "to fall ill" is rather clumsy, and "to get sick" is just repeating.
PLEASE try and be briefer and more to the point in these submissions.

@@ -13 +12,0 @@
-<gloss>to become ill</gloss>
@@ -15 +14 @@
-<gloss>to get sick</gloss>
+<gloss>to become indisposed</gloss>

https://dictionary.reverso.net/english-cobuild/indisposed+at+the+moment#:~:text=If you say that someone,do not want to reveal.
indisposed      
If you say that someone is indisposed, you mean that they are not available because they are ill, or for a reason that you do not want to reveal. 

https://www.collinsdictionary.com/dictionary/english/indisposed
indisposed
in American English
1.  slightly ill
2.  unwilling; disinclined
Websters New World Dictionary Includes:
Otherwise occupied; busy, unavailable, etc.

https://www.urbandictionary.com/define.php?term=Indisposed
Polite way of telling a business contact that you couldn't answer the phone because you were [in the bathroom]. 
"Sorry I couldn't answer your call. I was indisposed at the moment."

=====
体調を崩す
https://eikaiwa.dmm.com/uknow/questions/70077/
Fall ill
Feel sick
get sick

https://detail.chiebukuro.yahoo.co.jp/qa/question_detail/q10111791145
Q：体調を崩さぬよう気を付けてください？
A；Don't upset your health, and take care.

https://eow.alc.co.jp/search?q=体調を崩す
体調を崩す
upset [disturb] one's health
突然体調を崩す
suddenly become ill after
インフルエンザで体調を崩す
be ill with flu
心配が募って体調を崩す
make oneself (physically) sick with worry
高所障害で体調を崩す
suffer (from) altitude sickness

A tweet:
Lot's of students are working too hard and getting sick/falling ill.
春になり新しい環境への対応で、無理して体調を崩す生徒さんが増えています😰
https://twitter.com/azworldfriends/status/1643931564194123783
juxtaposed with a list of translated expressions:
I caught a cold
I have a fever
I have a stuffy nose
I have a headache
I have a sore throat.
= all reflections of 体調を崩す

https://ejje.weblio.jp/content/体調を崩す
become ill

To start off with, here's a fixed, common, polite expression(I can surmise the meaning, but I have not found a full English translation for this common expression):
体調を崩されませんようご自愛ください
Can you say in English "try not to become indisposed?"

Anyway, this is a surprisingly common term(worth refining, I think), apparently used as a negated command "don't get sick, don't overwork yourself, don't overdo it, etc.".  
体調を崩し	504144	  
体調を崩さ	124351	  （beginning of  expressions like 体調を崩されないよう 体調を崩さない...)
体調を崩す	88486	  
体調を崩しやすい	38826	 ("I get sick easily", I imagine)

I'm volunteering my ignorance here.  I was completely unaware that "indisposed" carried the meaning of "slightly unwell".

Growing up with phrases like "I'm a bit indisposed at the moment", I've come to believe this is a synonym for "temporarily unavailable due to being occupied with some other matter, call again later".  The collins note above "or for a reason that you do not want to reveal" euphemistic usage of the term has surely contributed to this transformation.

The usual reverso translation of "indisposed" is　具合が悪い, which seems like the right tone for general excuse-making. Might be a better fit as the last entry there, rather than here.

Because  "indisposed" was confusing for me, I'm going to make a second argument to drop it.  Everything I've read suggests that "indisposed" is supposed to reflect "mild illness".  It also seems to reflect something passive that "just happens", where as 体調を崩す seems quite a bit more severe(image results), and the verbiage seems to suggest that one has brought this on themselves in some way (through overwork, eating something undercooked, etc.). 

Moving on to my edits of the other glosses...
This looks like "a thing that happens".
"I/he got sick":
体調を崩してしまった
体調を崩した	65976
体調を崩してしまった	14563
体調を崩しちゃった	1058

Likewise the negated forms 体調を崩さないように "try to not get sick. look after your health, etc.". 

Seems like there is some overlap... 具合が悪い I am sick(or 体調を崩している 22523), 体調を崩した I got sick (具合が悪くなった?）

@@ -13,2 +13,3 @@
-<gloss>to become indisposed</gloss>
-<gloss>to feel unwell</gloss>
+<gloss>to become ill</gloss>
+<gloss>to fall ill</gloss>
+<gloss>to get sick</gloss>

GG5, Eijiro

@@ -12 +12,4 @@
-<gloss>for one's physical condition to deteriorate</gloss>
+<pos>&v5s;</pos>
+<gloss>to become indisposed</gloss>
+<gloss>to feel unwell</gloss>
+<gloss>to have one's physical condition deteriorate</gloss>

https://ejje.weblio.jp/content/体調を崩

Saw this used a few times in a LINE conversation. Current glosses of 崩す are related but not quite what this means in this context. Also not an obvious pair, hence the submission.