nonchalant

marked by blithe unconcern; "an ability to interest casual students"; "showed a casual disregard for cold weather"; "an utterly insouciant financial policy"; "an elegantly insouciant manner"; "drove his car with nonchalant abandon"; "was polite in a

और यह देखकर हैरान रह गया कि वह पूर्णतः उदासीन, निर्मम स्थिति में अपने प्रयोगों में व्यस्त रहे तथा बाहर निकलने से इन्कार कर दिया था।

And to my utter chagrin, I found him as nonchalant and indifferent as ever, totally engrossed in his experiment and loath to move out.