taru-adjective
Archaic taru-adjective describing a person's serene, unperturbed demeanor. Found mainly in classical literature; in modern Japanese, 悠然 or 落ち着いた are more common.
彼は寛然として、何事にも動じなかった。
He remained composed and unruffled by anything.
古典では「寛然たる態度」のように用いられることがある。
In classical texts, it is sometimes used in phrases like 'a calm and composed attitude'.