campaign has 15 distinct synonyms spread across 7 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 race between candidates for elective office
“I managed his campaign for governor”
a series of actions advancing a principle or tending toward a particular end
“he supported populist campaigns”
several related operations aimed at achieving a particular goal (usually within geographical and temporal constraints)
an overland journey by hunters (especially in Africa)
run, stand, or compete for an office or a position
“Who's running for treasurer this year?”
Synonyms, antonyms and the broader and narrower relations for campaign come from Princeton University’s WordNet. Full sources and licences.
exert oneself continuously, vigorously, or obtrusively to gain an end or engage in a crusade for a certain cause or person; be an advocate for
“The liberal party pushed for reforms”