This is the 8267th most frequent Japanese word.
康
"康" means "health" or "well-being."
In this sentence, "健康" (kenkō) means 'health,' where "康" contributes to forming the word indicating well-being.
彼は健康で長生きしている。
He is healthy and lives a long life.
Here, "康" is used in "心の康," indicating mental peace and wellness.
安心して過ごすことが心の康を保つ秘訣です。
Living with peace of mind is the secret to maintaining mental health.
In this example, "健康状態" refers to 'health condition,' using "康" within the term for general health.