Word parts soften + -er Pronunciation (US) IPA (key): /ˈsɔfənər/ (UK) (Canada) IPA (key): /ˈsɒfənər/ Noun Singular softener Plural softeners (countable) A softener is a chemical substance added to something in order to soften it.Wikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads