不行 (bù xíng): ไม่ไหว；เป็นไปไม่ได้；ไม่ดี；ใช้ไม่ได้；ไม่สามารถ

It's raining today; going to the park won't work.

This method won't do; we need to change to another one.

He is not physically capable; he can't run a marathon.

Will you help me do my homework, is that okay?

No, you cannot leave now.