cross-pollination has no recorded synonym. 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 self-pollination.
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.
fertilization by transfer of pollen from the anthers of one flower to the stigma of another
stimulating influence among diverse elements
“the cross-pollination of the arts”
Synonyms, antonyms and the broader and narrower relations for cross-pollination come from Princeton University’s WordNet. Full sources and licences.