zajebano

It's a bad serbocroatian word that describes something that is quite hard or impossible. It is an adjective, and as such, can be subjected to the comparison of adjectives.

That is so zajebano!

That was very zajebano!

That's gonna be zajebano to do...

Or, in serbocroatian: Ala je to zajebano!
Kako zajebano! Zajebali su te!