dream has 7 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.
a series of mental images and emotions occurring during sleep
“I had a dream about you last night”
imaginative thoughts indulged in while awake
“he lives in a dream that has nothing to do with reality”
Synonyms, antonyms and the broader and narrower relations for dream come from Princeton University’s WordNet. Full sources and licences.
a cherished desire
“his ambition is to own his own business”
a fantastic but vain hope (from fantasies induced by the opium pipe)
“I have this pipe dream about being emperor of the universe”
a state of mind characterized by abstraction and release from reality
“he went about his work as if in a dream”
someone or something wonderful
“this dessert is a dream”
experience while sleeping
“She claims to never dream”