When none happened, she went weak with relief, thinking: Who would guess?

Now we know the real meaning of going weak at the knees.

I just went weak all of a sudden, but it passed.

His voice was going weak, and the shivering had started again.

But it wasn't the act that made her legs suddenly go weak.

She went weak at the thought of him never waking.

This had been much more powerful - enough to make her knees go weak.

She's not going to go weak and helpless on you.

"But only because I haven't found anyone to pay me a living wage for going weak."

Mark's knees went weak and he leaned on the wall.