access has 8 distinct synonyms spread across 5 of its 8 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 right to obtain or make use of or take advantage of something (as services or membership)
a code (a series of characters or digits) that must be entered in some way (typed or dialed or spoken) to get the use of something (a telephone line or a computer or a local area network etc.)
(computer science) the operation of reading or writing stored information
Synonyms, antonyms and the broader and narrower relations for access come from Princeton University’s WordNet. Full sources and licences.