universal has 9 distinct synonyms spread across 4 of its 7 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 particular.
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.
(linguistics) a grammatical rule (or other linguistic feature) that is found in all languages
(logic) a proposition that asserts something of all members of a class
a behavioral convention or pattern characteristic of all members of a particular culture or of all human beings
“some form of religion seems to be a human universal”
coupling that connects two rotating shafts allowing freedom of movement in all directions
“in motor vehicles a universal joint allows the driveshaft to move up and down as the vehicle passes over bumps”
of worldwide scope or applicability
“an issue of cosmopolitan import”
2 of the 7 recorded senses carry no synonym, antonym or related term, so they are not shown above. Every sense, with its definition and examples, is on the full entry for universal.
Synonyms, antonyms and the broader and narrower relations for universal come from Princeton University’s WordNet. Full sources and licences.