腿发软

腿发软

Literally means:

legs are getting weak

Actually means:

be extremely nervous or tired

It means that one cannot stand the heavy physical burden or mental stress. It is often used to indicate that one is tired, nervous or scared.

人支持不住某种体力上的负担，或承受不了某种精神压力。常用来形容劳累、紧张或害怕。