I asked like a hundred people about this word. Almost all of them say they’ve never heard it spoken or read throughout all of their experiences as a Japanese person.
Yes, it’s outdated— colloquially of course. 
EDIT: I just asked 3 people in my office and they said they have never even heard of the word until now. They asked me if I made it up!
I made a post a long while ago about how it IS used, but in a very specific way and not the way that you would just say “I’m homesick”
Countdown to a reply demanding names and addresses of all 100 people who are absolutely unequivocally wrong and frankly dangerous to forum harmony
So basically you can only use it in the sense of X made me homesick?
At least, that’s the impression I got from your link
Its more to point out that that it’s almost always followed by 〜がつく
Even two of the three example sentences on Wanikani have it followed by 〜がつく or some conjugation of it.
So a natural way to use it would be to say (or write) something like 長旅「に」里心「がついた」
but it’s not like the hot word of the century.
It’s off-topic regarding 里心 in particular, but I feel it’s relevant either way:
It’s also especially funny to me because my own native language is going through the same process.
Okay, not 100, but a handful of people. What I’m saying is, sure, it exists as a word, but expect it to raise some eyebrows when using it.
One of my favorite Dogen videos. That ’yes’ at the end is so perfectly delivered.
I like spiraling threads like this. They 1. make sure you’ll burn this particular item off WK plate easily 2. provide bunch of extra funny information.
Remembered there was a heated thread on “Sakura viewing” a while ago, enforced 花見 for me for sure.
Did you catch this in the meaning explanation?
Young people don’t really use this word anymore. It’s more for the oldies. If you’re an oldie, go right ahead. If you’re a youngie, then talk to more oldies!
The question we must ask, then, is:
Is it even worth it?
At least give us a T-shirt for learning 2000 kanji
The way current modern literature (and by that I mean manga and light novels) is going, even if all the words will become English, they’ll still use kanji.
Like so: 脳嵐事
I saw 里心 once while reading, it was the best day of my life. Like @MrBaman said, it did have がつく after:
旅から旅の行商人であっても、言葉も食事も服装も違う異国に来ていれば里心がつくというものだからだ。
Darn! i was thinking about mentioning this video.
Good pick, グヅピック、フレインド。
グッド ピック でしたね
But it is certainly my favorite! Actually teaches you some history too, so I find it a very important word! <3
Right, ga tsuku… meaning something made something else homesick? Or do I have it wrong?
A long time ago on my first go-around here WK had a vocabulary word for ‘signpost’ that was so rarely used it wasn’t in any dictionaries that I could find except in one for archaic uses. When I posted on here I got all the “wanikani doesn’t do things wrong and is perfect and your post is cliche” replies.
They did end up changing it to a more commonly uesd word. I would suggest just emailing them instead of rustling all the jimmies in here.
Was that word, michishirube, by chance?
That word is in Jisho, so I’m guessing not.