soil has 13 distinct synonyms spread across 5 of its 5 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.
material in the top layer of the surface of the earth in which plants can grow (especially with reference to its quality or use)
“the land had never been plowed”
the geographical area under the jurisdiction of a sovereign state
“American troops were stationed on Japanese soil”
Synonyms, antonyms and the broader and narrower relations for soil come from Princeton University’s WordNet. Full sources and licences.