adverb, taru-adjective
calm and composed; cool and collected
Literary and rare; describes a person's serene, unruffled demeanor. Often used in classical or formal writing.
彼は寛緩として動じなかった。
He remained calm and unperturbed.
寛緩たる態度で交渉に臨んだ。
He approached the negotiations with an air of perfect composure.
The exact derivation is uncertain; the kanji 寛 (lenient, relaxed) and 緩 (loose, gentle) suggest a meaning of 'relaxed and calm'. The reduplicated form かんかん is likely a literary coinage.