For a woman to dream that she is dressed in nothing but her negligee means that she has a secret that she is fearful of having discovered.
New American Dream Dictionary
2. A desire to be noticed, admired.
3. A desire or need for intimacy. ... New American Dream Dictionary
Gypsy Dream Dictionary
2. A feeling of not being prepared for life, activities or business affairs (to be in a nightgown in public). ... New American Dream Dictionary
The Complete Dream Book
My Dream Interpretation
To see others in their in their nightgown in your dream, signifies that you will hear unpleasant news from absent friends.... My Dream Interpretation
Depth Psychology: The nightshirt or nightgown indicates hidden erotic desires and needs. It could also point to your own character and that of the people wearing the gown.... Dreamers Dictionary