noun
one's best clothes; Sunday best; formal wear
Refers to one's finest, most formal clothing, typically worn for special occasions like ceremonies, celebrations, or important events. Often implies traditional Japanese attire, but can also refer to Western formal wear.
成人式には、多くの女性が華やかな晴れ着を着る。
Many women wear gorgeous formal kimono for the Coming of Age ceremony.
彼は結婚式のために新しい
He bought new formal clothes for the wedding.
正装 refers to formal dress in general, often used for Western-style formal wear or uniforms, while 晴れ着 emphasizes one's personal best attire for celebratory occasions, frequently implying traditional Japanese clothing.
礼服 is specifically formal attire for ceremonies, such as mourning clothes or wedding attire, and is more rigidly defined than 晴れ着, which has a broader, more personal sense of 'best clothes'.
Compound of 晴れ (hare, 'fine weather; special occasion') and 着 (ki, 'clothing'), with rendaku voicing to ぎ. The word originally referred to clothes worn on clear, auspicious days, and by extension came to mean one's best clothes for special events.