planetary has 8 distinct synonyms spread across 4 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. 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.
of or relating to or resembling the physical or orbital characteristics of a planet or the planets
“planetary motion”
of or relating to or characteristic of the planet Earth or its inhabitants
“planetary rumblings and eructations”
involving the entire earth; not limited or provincial in scope
“global war”
Synonyms, antonyms and the broader and narrower relations for planetary come from Princeton University’s WordNet. Full sources and licences.