adhere has 10 distinct synonyms spread across 4 of its 6 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.
be compatible or in accordance with
“You must adhere to the rules”
follow through or carry out a plan without deviation
“They adhered to their plan”
come or be in close contact with; stick or hold together and resist separation
“The dress clings to her body”
Synonyms, antonyms and the broader and narrower relations for adhere come from Princeton University’s WordNet. Full sources and licences.