backward has 7 distinct synonyms spread across 4 of its 7 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 forward.
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.
in a manner or order or direction the reverse of normal
“it's easy to get the `i' and the `e' backward in words like `seize' and `siege'”
1 of the 7 recorded senses carries no synonym, antonym or related term, so it is not shown above. Every sense, with its definition and examples, is on the full entry for backward.
Synonyms, antonyms and the broader and narrower relations for backward come from Princeton University’s WordNet. Full sources and licences.