trip has 20 distinct synonyms spread across 9 of its 12 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 journey for some purpose (usually including the return)
“he took a trip to the shopping center”
a hallucinatory experience induced by drugs
“an acid trip”
a light or nimble tread
“he heard the trip of women's feet overhead”
Synonyms, antonyms and the broader and narrower relations for trip come from Princeton University’s WordNet. Full sources and licences.