flannelyoudaoicibaDictYouDict[flannel 词源字典]
flannel: [14] Flannel is probably one of the few Welsh contributions to the English language. It appears to be an alteration of Middle English flanen ‘sackcloth’, which was borrowed from Welsh gwlanen ‘woollen cloth’, a derivative of gwlān ‘wool’. This in turn is related to Latin lāna ‘wool’ and English wool. It is not clear where the British colloquial sense ‘insincere talk’ (which seems to date from the 1920s) comes from, although it may well have been inspired by Shakespeare’s unflattering application of the word to a Welshman in the Merry Wives of Windsor 1598: ‘I am not able to answer the Welsh flannel’, says Falstaff of Hugh Evans, a Welsh parson.
=> wool[flannel etymology, flannel origin, 英语词源]
flannel (n.)youdaoicibaDictYouDict
"warm, loosely woven woolen stuff," c. 1300, flaunneol, probably related to Middle English flanen "sackcloth" (c. 1400); by Skeat and others traced to Welsh gwlanen "woolen cloth," from gwlan "wool," from Celtic *wlana, from PIE *wele- (1) "wool" (see wool). "As flannel was already in the 16th c. a well-known production of Wales, a Welsh origin for the word seems antecedently likely" [OED].

The Welsh origin is not a universally accepted etymology, due to the sound changes involved; Barnhart, Gamillscheg, Diez suggest the English word is from an Anglo-French diminutive of Old French flaine "a kind of coarse wool." Modern French flanelle is a 17c. borrowing from English.