Nonchalant is an adjective that describes a person or behavior as appearing calm, relaxed, and unconcerned. It suggests a casual and indifferent attitude towards things that might normally cause stress or excitement.
Interesting fact: The word “nonchalant” originated from the French language, where “non” means “not” and “chalant” comes from “chaloir,” meaning “to concern.” So, nonchalant literally means “not concerned.”