x-ray has 6 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.
electromagnetic radiation of short wavelength produced when high-speed electrons strike a solid target
a radiogram made by exposing photographic film to X rays; used in medical diagnosis
Synonyms, antonyms and the broader and narrower relations for x-ray come from Princeton University’s WordNet. Full sources and licences.
take an x-ray of something or somebody
“The doctor x-rayed my chest”