intimate has 13 distinct synonyms spread across 9 of its 11 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.
involved in a sexual relationship
“the intimate (or sexual) relations between husband and wife”
thoroughly acquainted through study or experience
“this girl, so intimate with nature”
someone to whom private matters are confided
2 of the 11 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 intimate.
Synonyms, antonyms and the broader and narrower relations for intimate come from Princeton University’s WordNet. Full sources and licences.