business has 15 distinct synonyms spread across 6 of its 9 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 commercial or industrial enterprise and the people who constitute it
“he bought his brother's business”
the activity of providing goods and services involving financial and commercial and industrial aspects
“computers are now widely used in business”
the principal activity in your life that you do to earn money
“he's not in my line of business”
a rightful concern or responsibility
“it's none of your business”
the volume of commercial activity
“business is good today”
business concerns collectively
“Government and business could not agree”
incidental activity performed by an actor for dramatic effect
“his business with the cane was hilarious”
Synonyms, antonyms and the broader and narrower relations for business come from Princeton University’s WordNet. Full sources and licences.