adj. Indifferent; unconcerned; behaving as if detached.
the GNU version of the Collaborative International Dictionary of English
adj. Indifferent; careless; cool.
The Century Dictionary and Cyclopedia
Indifferent; unconcerned; careless; cool: as, he replied with a nonchalant air.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. marked by blithe unconcern
Word Usage
"At that moment, she gave a new meaning to the word nonchalant when she casually adjusted her right foot to let her arm rest on her knee and placed the other foot on the floor."