abstract has 18 distinct synonyms spread across 4 of its 9 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 concrete.
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.
consider a concept without thinking of a specific example; consider abstractly or theoretically
consider apart from a particular case or instance
“Let's abstract away from this particular example”
existing only in the mind; separated from embodiment
“abstract words like `truth' and `justice'”
not representing or imitating external reality or the objects of nature
“a large abstract painting”
1 of the 9 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 abstract.
Synonyms, antonyms and the broader and narrower relations for abstract come from Princeton University’s WordNet. Full sources and licences.