(每日一词) ineffable

ineffable  /ˌɪnˈef.ə.bəl/ adj. （尤指喜悦）言语难以表达的，不可言喻的

Meaning: causing so much emotion, especially pleasure, that it cannot be described

前缀: in-同im-否定, ef-同ex-表示向外

词根: fa-说话

后缀: -able 形容词后缀

e.g. The beauty of the sunrise was ineffable. 日出的美是难以言表的。