UMD students have until the 10th day of classes to adjust their schedule. That means you can drop a class without a W on your final transcript by the 10th day of classes (February 7, 2017). After that day, and before April 5, 2017, any class(es) dropped from the semester will show up with a W.
If you are on the waitlist for a class, go to class and reach out to the professor and ask what the chances are you'll get in. Keep looking for alternative classes in case you don't get in within the 10th day of classes.