DELETERIOUS Meaning of DELETERIOUS in English deleterious BrE AmE ˌdel ɪ ˈtɪər i‿əs ◂ ˌdiːl-, ˌ•ə- AmE \ -ˈtɪr-▷ deleterious|ly li▷ deleterious|ness nəs nɪs Longman Pronunciation English Dictionary. Английский словарь произношений Longman. 2012