na-adjective
nonchalant; unconcerned; casual
Describes a relaxed, carefree, or indifferent attitude. Often used for a person's demeanor or style.
from French
彼はいつもノンシャランな態度で、あまり細かいことを気にしない。
He always has a nonchalant attitude and doesn't worry about small details.
その俳優のノンシャランなファッションが若
The actor's casual fashion is popular among young people.