(as) clear as mud
US /əz klɪr əz mʌd/
UK /əz klɪr əz mʌd/

1.
so klar wie Kloßbrühe, völlig unverständlich
very difficult to understand; not clear at all
:
•
His explanation of the new policy was as clear as mud.
Seine Erklärung der neuen Politik war so klar wie Kloßbrühe.
•
The instructions for assembling the furniture were as clear as mud, so I had to guess.
Die Anweisungen zum Zusammenbau der Möbel waren so klar wie Kloßbrühe, also musste ich raten.