happiness 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. Its 2 recorded opposites are unhappiness, sadness.
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.
state of well-being characterized by emotions ranging from contentment to intense joy
Synonyms, antonyms and the broader and narrower relations for happiness come from Princeton University’s WordNet. Full sources and licences.
emotions experienced when in a state of well-being