UNSUBSTANTIATED Meaning of UNSUBSTANTIATED in English unsubstantiated BrE AmE ˌʌn səb ˈstæn t ʃ i eɪt ɪd ◂ § ˌ•sʌb-, -əd AmE -eɪt̬- Longman Pronunciation English Dictionary. Английский словарь произношений Longman. 2012