Nonchalant means acting calm and unconcerned, as if something doesn't bother you at all. When you're nonchalant, you appear relaxed and casual even in situations where others might be nervous or excited.

Picture a student who just won the science fair acting like it's no big deal, giving a little shrug when congratulated. Or imagine someone asking a friend for help moving heavy boxes, and the friend responding with a nonchalant “Sure, why not?” as if it's nothing. That casual, unbothered attitude is being nonchalant.

Someone might walk into an important meeting with a nonchalant attitude, stroll nonchalantly past a celebrity, or give a nonchalant wave to someone they haven't seen in years.

Being nonchalant can be admirable when it shows confidence and grace under pressure. A pilot might speak to passengers with nonchalant calm during turbulence, helping them stay calm. But sometimes people act nonchalant to hide their true feelings, pretending they don't care about something that actually matters to them quite a bit. The key is that nonchalant describes the outward appearance of being relaxed and casual, whether that reflects what's really going on inside or not.