expression, i-adjective
carefree; free from worry
Describes a person or expression that is untroubled, cheerful, and without visible anxiety.
彼女の屈託のない笑顔に、みんなが元気づけられた。
Everyone was cheered up by her carefree smile.
子供たちは屈託のない様子で遊んでいる。
The children are playing in a carefree manner.
From 屈託 (worry, concern) + の (possessive particle) + ない (not exist). Literally 'without worry'.