(Pokemon Sun) A Wingull in the Poke'Pelago had the whole thing where it wants to join you. So I let it join my boxes and it asked me if I wanted to nickname it, I entered "Soba Noodles" and it gave me a red flag. I removed "Soba" and then it was fine. Where is the reasoning for censoring the word "Soba?"
I tried nicknaming a Pokemon "soba" and it stopped me. Then I tried calling it "sob" and it stopped me. Then I tried "so", and it let me call it that. Then I tried "ob" and it let me call it that too.
So the banned word is "sob". I can't figure out the rude connotations of that word, but maybe it means something rude in another language, since the nickname censor probably still looks for words other than the language you're using. I say probably because from generation 6 and onwards, all the Pokemon games use the 3DS's built-in censor, which isn't on the internet and I'm not a hacker so I can't find that list. But if you want, here is the list of censored nicknames in gen 5 (reader discretion advised).