transalpine 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.
one living on or coming from the other side of the Alps from Italy
on or relating to or characteristic of the region or peoples beyond the Alps from Italy (or north of the Alps)
“ancient transalpine Gaul was an area northwest of the Alps and included modern France and Belgium”
Synonyms, antonyms and the broader and narrower relations for transalpine come from Princeton University’s WordNet. Full sources and licences.