The word Cirno's actually asking about is "majikichi", which is short for "maji de kichiku", or "a total monster". The joke wasn't working in English, so I improvised.
Actually, "majikichi" is a slang for "a certifiable madman". (See dic.pixiv.net )(Japanese) Marisa taught Cirno a false meaning ("a total monster") in joke.
However, glasnost's work is also good.
That's great.
Well, the tuition's ¥1,000,000."You're nuts"?I see~
Now I get it!It's slang for "You're insane."You're nuts.It's a phrase you can use when someone's being completely unreasonable.Marisa~Hmn?Teach me!Well, that's...What does "you're nuts" mean?