What's "waste a day" mean?

Native speaker’s answer
Rebecca
To "waste a day" means to be unproductive and not do anything that you need to do for the day, but rather spend time doing things you maybe want to do or just for fun. So the time is "wasted" and not put to good use. Ex: That meeting was a waste of time. They could have sent an email instead! Ex: I wasted a whole day watching TV instead of doing work.