worth has 2 distinct synonyms spread across 2 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. Its one recorded opposite is worthlessness.
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.
an indefinite quantity of something having a specified value
“10 dollars worth of gasoline”
the quality that renders something desirable or valuable or useful
French couturier (born in England) regarded as the founder of Parisian haute couture; noted for introducing the bustle (1825-1895)
(often used ironically) worthy of being treated in a particular way
“an idea worth considering”
1 of the 5 recorded senses carries no synonym, antonym or related term, so it is not shown above. Every sense, with its definition and examples, is on the full entry for worth.
Synonyms, antonyms and the broader and narrower relations for worth come from Princeton University’s WordNet. Full sources and licences.