clean has 26 distinct synonyms spread across 20 of its 31 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. Its 2 recorded opposites are dirty, unclean.
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.
free from dirt or impurities; or having clean habits
“children with clean shining faces”
ritually clean or pure
not spreading pollution or contamination; especially radioactive contamination
“a clean fuel”
(of behavior or especially language) free from objectionable elements; fit for all observers
“good clean fun”
exhibiting or calling for sportsmanship or fair play
“a clean fight”
free from clumsiness; precisely or deftly executed
“he landed a clean left on his opponent's cheek”
a weightlift in which the barbell is lifted to shoulder height and then jerked overhead
5 of the 31 recorded senses carry no synonym, antonym or related term, so they are not shown above. Every sense, with its definition and examples, is on the full entry for clean.
Synonyms, antonyms and the broader and narrower relations for clean come from Princeton University’s WordNet. Full sources and licences.
clean and tidy up the house
“She housecleans every week”
deprive wholly of money in a gambling game, robbery, etc.
“The other players cleaned him completely”
remove while making clean
“Clean the spots off the rug”
remove shells or husks from
“clean grain before milling it”