airing dirty laundry

Airing your dirty laundry refers to airing your dirty laundry in public where everyone can see it. The meaning behind airing your laundry (usually spoken as that you should not air your dirty laundry) is that you should not reveal aspects of your private life in public that should be kept private such as telling secrets, private details about you or your family, having a public argument, and other things that should be kept private.