ineffableyoudaoicibaDictYouDict[ineffable 词源字典]
ineffable: [15] Ineffable literally means ‘that cannot be spoken’. Its ultimate source was the Latin verb fārī ‘speak’, which has also given English fable, fame, fate, etc. Addition of the prefix ex- ‘out’ produced effārī ‘speak out’, from which the adjective ineffābilis was derived. In 19th-century English the word was used as a plural noun, like unmentionables, as a humorous euphemism for ‘trousers’ or ‘nether garments’: ‘shoes off, ineffables tucked up’, William Cory, Letters and Journals 1867.
=> fable, fame, fate[ineffable etymology, ineffable origin, 英语词源]
ineffable (adj.)youdaoicibaDictYouDict
late 14c., from Old French ineffable (14c.) or directly from Latin ineffabilis "unutterable," from in- "not, opposite of" (see in- (1)) + effabilis "speakable," from effari "utter," from ex- "out" (see ex-) + fari "to say, speak," from PIE root *bha- (2) "to speak, tell, say" (see fame (n.)). Plural noun ineffables was, for a time, a jocular euphemism for "trousers" (1823). Related: Ineffably.