interference has 10 distinct synonyms spread across 4 of its 5 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 noninterference.
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.
a policy of intervening in the affairs of other countries
(American football) blocking a player's path with your body
“he ran interference for the quarterback”
any obstruction that impedes or is burdensome
Synonyms, antonyms and the broader and narrower relations for interference come from Princeton University’s WordNet. Full sources and licences.