generally an uncomfy situation
this party is totaly scetch, lets leave
there is a scetch guy following us
But the other meaning of this word is a mix of the two words above. Many believe some norwegian people invented this word, but we can't be sure.
If you're spooked by a déjà vu, for example, you'd normally say "Spooky,". Or scary, of course. If something happens very coincidentally but appears to you as very planned and unexpected at the same time, this word, scetchy, matches for the situation.
It can also be used as an exclamation for a unpleasant situation.
All in all the word can be used for a dozen occasions, and there's actually no hundred percent detailed defination for it. Just use it when something is scary and spooky at the same time.
"It is scetchy to take off for a spring and fall ten meters down and into the water."