sketchy ... is slang for: something that is not right, something that is fake or dishonest
for example: I saw an ad for a job, but the company was not real ... it seemed sketchy.
A sketch is a picture that is rough, not finished.
This blog is mainly to explain a different English language expression every day. Sometimes I post other stuff. I also have a YouTube channel which is mostly about computer software: https://www.youtube.com/englishspacedog