If you describe someone as ~, you mean that they appear not to worry or care about things and that they seem very calm.
Clark’s mother is ~ about her role in her son’s latest work...
It merely underlines our rather more ~ attitude to life.
= casual
ADJ
nonchalance
Affecting nonchalance, I handed her two hundred dollar bills.
N-UNCOUNT
~ly
‘Does Will intend to return with us?’ Joanna asked as ~ly as she could.
= casually
ADV: usu ADV with v, also ADV adj