When something seems not quite right or makes you feel uneasy or suspicious.
Sketchinesses are usually not good because they make you feel worried or unsure about something.
Examples:
The dark alley had a lot of sketchinesses.
I don't trust that person because of their sketchinesses.
The sketchinesses of the situation made me feel uncomfortable.
The sketchinesses of the old house gave me the creeps.
There were so many sketchinesses about the deal that I decided not to go through with it.
The sketchinesses of the plan were too much for me to handle.