a person's body that has a lot of firm muscles and very little fat, or someone with a body like this

They're always at the gym maintaining their hard bodies. 他们总是在健身房里锻炼自己肌肉发达的身体。

I'm not interested in a bunch of 20-year-old hard bodies. 我对一群20岁、肌肉发达的人可没有什么兴趣。