the condition of being physically fit and healthy. "disease and lack of fitness are closely related"
noun [具体名词] 健康；（生物体的）环境适度；适合，胜任
He's too hung up about fitness. 他对健身过于忧心忡忡。
fit(健康的) + ness(名词后缀) → 健康
He's too hung up about fitness. 他对健身过于忧心忡忡。