divide has 10 distinct synonyms spread across 7 of its 8 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 unite, multiply.
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.
act as a barrier between; stand between
“The mountain range divides the two countries”
a serious disagreement between two groups of people (typically producing tension or hostility)
a ridge of land that separates two adjacent river systems
Synonyms, antonyms and the broader and narrower relations for divide come from Princeton University’s WordNet. Full sources and licences.