Noah Webster's New International Dictionary of the English Language

1. (superl.) Abounding in mud; besmeared or dashed with mud; as, a muddy road or path; muddy boots.

2. (superl.) Turbid with mud; as, muddy water.

3. (superl.) Consisting of mud or earth; gross; impure.

4. (superl.) Confused, as if turbid with mud; cloudy in mind; dull; stupid; also, immethodical; incoherent; vague.

5. (superl.) Not clear or bright.

6. (v. t.) To soil with mud; to dirty; to render turbid.

7. (v. t.) Fig.: To cloud; to make dull or heavy.