origin has 19 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.
the place where something begins, where it springs into being
“the Italian beginning of the Renaissance”
properties attributable to your ancestry
“he comes from good origins”
an event that is a beginning; a first part or stage of subsequent events
the point of intersection of coordinate axes; where the values of the coordinates are all zero
the source of something's existence or from which it derives or is derived
“the rumor had its origin in idle gossip”
Synonyms, antonyms and the broader and narrower relations for origin come from Princeton University’s WordNet. Full sources and licences.