a girl who does sketchy things. Girls can do many things to earn the term of being dubbed a sketchmister. In other words. If you are a female, do not fuck up. If you do then guys will be able to call you a sketchmeister in a derogatory fashion.
Amanda and I were having a fun time one night together just hanging out. At ten o'clock she says, "Im going go hang out with a couple and go tping at twelve thirty tonite" Me and my buddy were like ok. Thats a really random and sketchy thing to do. After she said this, she was officialy the first sketchmeister.