muddiness has 8 distinct synonyms spread across 3 of its 3 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
the wetness of ground that is covered or soaked with water
“the baseball game was canceled because of the wateriness of the outfield”
a mental state characterized by a lack of clear and orderly thought and behavior
“a confusion of impressions”
the quality of being cloudy
Synonyms, antonyms and the broader and narrower relations for muddiness come from Princeton University’s WordNet. Full sources and licences.