boss has 11 distinct synonyms spread across 6 of its 7 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 person who exercises control over workers
“if you want to leave early you have to ask the foreman”
a person who exercises control and makes decisions
“he is his own boss now”
a leader in a political party who controls votes and dictates appointments
“party bosses have a reputation for corruption”
Synonyms, antonyms and the broader and narrower relations for boss come from Princeton University’s WordNet. Full sources and licences.