noun, na-adjective
Formal, literary term used mainly in letters and New Year's cards, often in the phrase ご健勝をお祈り申し上げます.
皆様のご健勝をお祈り申し上げます。
I wish you all good health.
年賀状には「ご健勝」と書くことが多い。
People often write 'ご健勝' on New Year's cards.
健康 is the everyday word for health; 健勝 is a formal, written-only expression used in greetings.
Compound of 健 (healthy) and 勝 (superior, excellent), suggesting robust health. The exact historical derivation is uncertain.