projection has 9 distinct synonyms spread across 4 of its 10 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 prediction made by extrapolating from past observations
the projection of an image from a film onto a screen
(psychiatry) a defense mechanism by which your own traits and emotions are attributed to someone else
the acoustic phenomenon that gives sound a penetrating quality
“our ukuleles have been designed to have superior sound and projection”
the representation of a figure or solid on a plane as it would look from a particular direction
the act of expelling or projecting or ejecting
Synonyms, antonyms and the broader and narrower relations for projection come from Princeton University’s WordNet. Full sources and licences.