I find “where did you learn such a word” kind of questions funny. If you watch anime or read manga or novels it’s bound to show up. It’s a good word to know! You just need to know in which contexts it’s okay to use it.
Wanikani does say that 飯 “has a slightly gruff feel to it” but from the sounds of it, your 先生 found it on the “offensive” side? Or was she just correcting you on using it in a formal setting?
I must have missed the memo in Tsurukame. Yeah, she said “rude,” but like I said she was so nice about it and laughed. More than likely because we were in the formal setting and she wanted other students to also know.
Oh yeah of course, it’s good to know when certain words should only be reserved for certain contexts, if anything to teach people when not to say them.
Kind of like the practice of teaching foreigners swear words so that they don’t accidentally use them, lmao.
Ok so we have 便所, お手洗い, and トイレ…and probably more that I just haven’t learned yet.
I feel like that’s already too many ways to say bathroom, but then again English isn’t really any less guilty of this, lol. But as far as I know, there’s just one word “bathroom” that’s acceptable in all contexts in English, which I guess keeps it simple.