B2 not obvious or easy to see or know:
The ownership of the painting remains unclear.
[ + question word ] It's unclear what actually happened that night.
It's unclear whether he arrived before or after the shot was fired.
B2 If you are unclear about something, you are not certain about it:
I'm unclear about a couple of points in your proposal - could you go over them again?
I'm unclear (as to) whether we're supposed to stay here or not.