brush has 10 distinct synonyms spread across 6 of its 15 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.
a dense growth of bushes
an implement that has hairs or bristles firmly set into a handle
conducts current between rotating and stationary parts of a generator or motor
a bushy tail or part of a bushy tail (especially of the fox)
the act of brushing your teeth
“the dentist recommended two brushes a day”
contact with something dangerous or undesirable
“I had a brush with danger on my way to work”
rub with a brush, or as if with a brush
“Johnson brushed the hairs from his jacket”
clean with a brush
“She brushed the suit before hanging it back into the closet”
remove with or as if with a brush
“brush away the crumbs”
cover by brushing
“brush the bread with melted butter”
Synonyms, antonyms and the broader and narrower relations for brush come from Princeton University’s WordNet. Full sources and licences.