worker has 4 distinct synonyms spread across 2 of its 4 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 one recorded opposite is nonworker.
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 member of the working class (not necessarily employed)
“workers of the world--unite!”
sterile member of a colony of social insects that forages for food and cares for the larvae
a person who acts and gets things done
“he's a principal actor in this affair”
Synonyms, antonyms and the broader and narrower relations for worker come from Princeton University’s WordNet. Full sources and licences.