to play hard ball 采取不正当手段来达到目的

to play hard ball – to be so determined to get what you want that you will use unfair methods to get it.

打硬式棒球 - 决心要得到自己想要得到的以至于要采取一些不正当的手段来达到目的

例句：

The people here like to play hard ball which can be very challenging. (Ball games)

这里的人喜欢采取强硬手段，可能会极具挑战性。（球类运动）