adhesion has 4 distinct synonyms spread across 2 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.
a fibrous band of scar tissue that binds together normally separate anatomical structures
the property of sticking together (as of glue and wood) or the joining of surfaces of different composition
“the mutual adhesiveness of cells”
faithful support for a cause or political party or religion
“attachment to a formal agenda”
Synonyms, antonyms and the broader and narrower relations for adhesion come from Princeton University’s WordNet. Full sources and licences.