inspiration has 7 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.
a product of your creative thinking and work
“he had little respect for the inspirations of other artists”
a sudden intuition as part of solving a problem
(theology) a special influence of a divinity on the minds of human beings
“they believe that the books of Scripture were written under divine guidance”
the act of inhaling; the drawing in of air (or other gases) as in breathing
Synonyms, antonyms and the broader and narrower relations for inspiration come from Princeton University’s WordNet. Full sources and licences.