Shigaon - שִׁגָּעוֹן
Literal translation: Wonderful, terrific
Like many words in Hebrew, the word shigaon can have more than one meaning. It can either mean everything is great or terrific, but on the other hand, it can also mean a state of madness or insanity.
So if you ask an Israeli how he or she is doing, and the answer is shigaon, don't worry. They're probably doing fine.