In episode 10 of Love Live season one, when Yazawa Nico is woken up and everyone sees her facial mask, Ayase Eli comments saying "Khorosho". She says this also when Sonoda Umi is woken up and turns into a "demon". Given the context, I thought "Khorosho" meant something like "scary" or "frightening" but it was weird that NISA didn't change this in the English subtitles.
However, at the end of the episode when all the girls are on the beach holding hands and watching the sunrise, when Nishikino Maki thanks her, Eli says "Khorosho" and also Eli's sister Alisa says "Khorosho" when she's corrected in thinking that a red bean bun was a cream puff in episode 12. In both of these situations, I can't really imagine "Khorosho" meaning "scary".
So what does "Khorosho" mean? And why wouldn't it be translated in the English subtitles?