occupation has 7 distinct synonyms spread across 3 of its 5 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.
the principal activity in your life that you do to earn money
“he's not in my line of business”
the control of a country by military forces of a foreign power
any activity that occupies a person's attention
“he missed the bell in his occupation with the computer game”
the act of occupying or taking possession of a building
“occupation of a building without a certificate of occupancy is illegal”
the period of time during which a place or position or nation is occupied
“during the German occupation of Paris”
Synonyms, antonyms and the broader and narrower relations for occupation come from Princeton University’s WordNet. Full sources and licences.