1. showing a relaxed lack of concern or interest; casually calm and indifferent

Examples

• She gave a nonchalant shrug when asked about the test results.
• His nonchalant attitude toward the deadline worried his boss.
• Despite the chaos around her, she remained nonchalant and composed.
• He walked into the interview with a nonchalant air of confidence.
• The celebrity responded to the criticism with nonchalant indifference.
• Her nonchalant response surprised everyone who expected her to be upset.