Chinese Idioms --- 光打雷不下雨

光打雷不下雨。

Guāng dǎléi bú xiàyǔ.
光打雷不下雨。
only thunder no rain.

It is a commonly used idiom in Chinese spoken language. It has a derivative sentence –雷声大雨点小Léishēng dà, yǔdiǎn xiǎo, which has very close meaning to the original one. As for the figurative meaning, can you make a guess what the message is?

Yes, your instinct is right and it means only talk but no action. Isn’t it so true that there are always people who can talk really big but indeed won’t make anything out of his big word? It’s like quite some thundering while you think wow, it’s going to be a huge storm while it ends up with just two drops of rain.

Big talks won’t have any real effect, normally. All in all, the words are hypothetical themselves. However, it decreases the level of trustworthy of the people whoever does that. In intimate relationships, it will hurt the feelings when you promise big but never redeem them. Therefore, be cautious about the things you say. It feels good when you seem to be able to achieve a lot, but down to the earth, you know how far you can go.
 
Example:
     
A: 老板说要给我们加工资。
The boss said he would give us a pay rise.
B: 别太当真，也许又是光打雷不下雨。
Don't take it serious, maybe there's only thunder but no rain.