Meaning of the word "(as) clear as mud" in English

What does "(as) clear as mud" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

(as) clear as mud

US /əz klɪr əz mʌd/
UK /əz klɪər əz mʌd/
"(as) clear as mud" picture

Idiom

very difficult to understand; not clear at all

Example:
His explanation of the new policy was as clear as mud.
The instructions for assembling the furniture were as clear as mud, so I had to guess.