dirty little secret
noun phrase - Something shameful that must be concealed; an embarrassing fact: Power has been a dirty little secret among modern economists
- Anything held secret personally or communally because it is patently shameful; a skeleton in the closet: Everybody will know the dirty little secret of American journalism/ Class Act: America's Last Dirty Little Secret
[phrase propagated by D H Lawrence, esp in his long essay ''Pornography and Obscenity'']