cool; up with the shit.
The new jacket Hannah got is so fasho!
In Europe, it is in many countries the short form of fashist.
In Germany, for instance, "ein Fascho" translates to "a fashist", or "das ist aber fascho" (eng. "that is so fashist"). Even Google Translator translated "Er ist ein Fascho" into "He is a fascist", and equivalent to "fascho" (adjective).
It is, however, not related to the American Black slang of "fasho" as "for sure".
That was so fasho.
You are a fasho.
That party is fasho.