caput has 1 distinct synonym spread across 1 of its 2 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 headlike protuberance on an organ or structure
“the caput humeri is the head of the humerus which fits into a cavity in the scapula”
the upper part of the human body or the front part of the body in animals; contains the face and brains
“he stuck his head out the window”
Synonyms, antonyms and the broader and narrower relations for caput come from Princeton University’s WordNet. Full sources and licences.