健康

It is the standard word for physical wellbeing — a 健康的人 (healthy person), 健康的食物 (healthy food), 身体健康 ('good physical health,' a common toast and birthday wish). Unlike English 'healthy,' which colloquially extends to portion sizes ('a healthy serving') or attitudes, Chinese 健康 stays close to the literal meaning of bodily or mental wellness.

Two patterns matter: as a predicate adjective it follows the noun (他很健康, 'he is healthy'), and as a noun it commonly takes 保持 (bǎochí, 'maintain') — 保持健康 ('maintain health'). The phrase 身体健康 (shēntǐ jiànkāng, 'good health') is so embedded in social ritual that it appears in nearly every toast, Spring Festival greeting, and birthday card.