condition

in (或 out of) condition

in a fit (or unfit) physical state

健康状况良好（或不佳）

in no condition to do something

certainly not fit or well enough to do something

（健康状况，身体状况）不适宜做某事

you’re in no condition to tackle the stairs.

你的身体不适宜爬楼梯。

on condition that

with the stipulation that

如果…就；只有在…条件下

I got three years' probation, on condition that I stay at the hostel for a year.

我得到三年试用期，条件是我必须在招待所呆满一年。