nonchalant

UK: /ˈnɒnʃələnt/

US: /ˌnɑnʃəˈlɑnt, ˈnɑnʃəˌlɑnt, -lənt/

US: (non′shə länt′, non′shə länt′, -lənt)

WordReference Random House Learner's Dictionary of American English © 2025

non•cha•lant /ˌnɑnʃəˈlɑnt, ˈnɑnʃəˌlɑnt, -lənt/   adj. 

1. coolly unconcerned;
   indifferent;
   offhand.

non•cha•lance, n. [uncountable]
non•cha•lant•ly, adv. 

WordReference Random House Unabridged Dictionary of American English © 2025

non•cha•lant  (non′shə länt′, non′shə länt′, -lənt), adj. 

1. coolly unconcerned, indifferent, or unexcited;
   casual:
   His nonchalant manner infuriated me.

• Latin calēre to be warm. See -ant
• French nonchalant, present participle of obsolete nonchaloir to lack warmth (of heart), be indifferent, equivalent. to non- non- + chaloir
• 1725–35

non′cha•lant′ly, adv. 
Synonyms

cool, calm, collected, composed.

Antonyms

excitable.

Collins Concise English Dictionary © HarperCollins Publishers::

nonchalant / ˈnɒnʃələnt/ adjective

1. casually unconcerned or indifferent; uninvolved

Etymology: 18th Century: from French, from nonchaloir to lack warmth, from non- + chaloir, from Latin calēre to be warm

ˈnonchalance noun