nonchalantyoudaoicibaDictYouDict[nonchalant 词源字典]
nonchalant: [18] To be nonchalant is etymologically ‘not to get hot under the collar’. The word comes from French nonchalant, an adjective formed with the prefix non- ‘not’ from the present participle of the verb chaloir ‘be concerned’. This goes back ultimately to Latin calēre ‘be hot’ (a relative of English calorie and cauldron).
=> calorie, cauldron, lukewarm[nonchalant etymology, nonchalant origin, 英语词源]
nonchalant (adj.)youdaoicibaDictYouDict
1734, from French nonchalant, present participle of nonchaloir "be indifferent to, have no concern for" (13c.), from non- "not" (see non-) + chaloir "have concern for," ultimately from Latin calere "be hot" (see calorie). French chaland "customer, client" is of the same origin. Related: Nonchalantly.