a subject or problem that people do not know how to deal with because there are no clear rules
niezbadany teren, szara strefa
The legal difference between negligence and recklessness is a bit of a grey area.
There's a large gray area between what is legal and what is not
I do well in math and most sciences, but chemistry is still kind of a grey area.
W USA mówi się "gray area", a nie "grey area"