s has 13 distinct synonyms spread across 5 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.
1/60 of a minute; the basic unit of time adopted under the Systeme International d'Unites
an abundant tasteless odorless multivalent nonmetallic element; best known in yellow crystals; occurs in many sulphide and sulphate minerals and even in native form (especially in volcanic regions)
the cardinal compass point that is at 180 degrees
a unit of conductance equal to the reciprocal of an ohm
the 19th letter of the Roman alphabet
(thermodynamics) a thermodynamic quantity representing the amount of energy in a system that is no longer available for doing mechanical work
“entropy increases as matter and energy in the universe degrade to an ultimate state of inert uniformity”
Synonyms, antonyms and the broader and narrower relations for s come from Princeton University’s WordNet. Full sources and licences.