dandy; gallant; chivalrous man
Historical term for a stylish, chivalrous man, often associated with the Edo-period culture of 伊達 (date). Now mostly encountered in historical or literary contexts.
He was dressed in a kimono like an Edo-period dandy.
That person is affecting the airs of a gallant.
Compound of 伊達 (date, 'stylishness, chivalry') and 衆 (shū, 'group of people'). The exact origin of 伊達 is uncertain, but it is associated with the Date clan of Sendai, known for their flamboyant style.