heterosexual has 3 distinct synonyms 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 homosexual, bisexual.
a person having a sexual orientation to persons of the opposite sex
sexually attracted to members of the opposite sex
Synonyms, antonyms and the broader and narrower relations for heterosexual come from Princeton University’s WordNet. Full sources and licences.
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.