dirty laundry

Translations
грязное белье
It's not wise to air their dirty laundry in public.
Неразумно выносить их грязное белье на публику.
Definitions
Dirty laundry refers to personal or private matters that are embarrassing or scandalous, often implying that these issues should not be made public. It can also literally mean soiled clothing that needs to be washed.
Words
dirty

adjective
грязный
laundry

noun
бельё