backlashEnglishOxford New American Dictionarybacklash /ˈbakˌlaSH, ˈbækˌlæʃ / ▸ noun 1 [in singular] a strong and adverse reaction by a large number of people, especially to a social or political development: a public backlash against racism. 2 recoil arising between parts of a mechanism. ▪ degree of play between parts of a mechanism: typical gearbox backlash in these systems is 2°.