bubble has 9 distinct synonyms spread across 3 of its 9 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 hollow globule of gas (e.g., air or carbon dioxide)
a speculative scheme that depends on unstable factors that the planner cannot control
“his proposal was nothing but a house of cards”
Synonyms, antonyms and the broader and narrower relations for bubble come from Princeton University’s WordNet. Full sources and licences.
an impracticable and illusory idea
“he didn't want to burst the newcomer's bubble”
a dome-shaped covering made of transparent glass or plastic