declarative has 7 distinct synonyms spread across 3 of its 3 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 interrogative.
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.
relating to the use of or having the nature of a declaration
relating to the mood of verbs that is used simple in declarative statements
“indicative mood”
a mood (grammatically unmarked) that represents the act or state as an objective fact
Synonyms, antonyms and the broader and narrower relations for declarative come from Princeton University’s WordNet. Full sources and licences.