magnanimous; broad-minded; generous in spirit
A somewhat literary or formal expression describing a person of great magnanimity and broad-mindedness. Often used to praise someone's tolerant and generous character.
I was impressed by his magnanimous attitude.
A truly broad-minded person is a real leader.
寛大 is more common and means 'generous' or 'lenient', often in forgiving mistakes. 気宇広大 is more literary and emphasizes a grand, noble broad-mindedness of character.
度量が大きい is a common phrase for 'broad-minded' or 'big-hearted'. 気宇広大 is a more formal, Sino-Japanese compound with a similar meaning but a more elevated tone.
A Sino-Japanese compound (四字熟語) composed of 気宇 (spirit, mind) and 広大 (vast, broad). The exact historical derivation is uncertain, but it follows classical Chinese patterns for describing noble character.