1. (noun)nonchalance, unconcern, indifference the trait of remaining calm and seeming not to care; a casual lack of concern Synonyms: nonchalance, indifference, impassivity, phlegm, unconcern, spiritlessness, numbness, apathy, emotionlessness, impassiveness, stolidity, unemotionality Antonyms: concern
2. (noun)unconcern a feeling of lack of concern Synonyms: indifference, nonchalance Antonyms: concern