English Proverb: Let sleeping dogs lie
The meaning of let sleeping dogs lie is quite simple, really: do not wake up a sleeping dog. Why? Well, a sleeping dog is not dangerous. However, if you wake up a sleeping dog, she may bite you.
In other words, do not bring up a topic which could cause trouble if you are not experiencing any problems now.
Now when can you use this idiom?
Well, let’s imagine that you have just heard that seven weeks ago your co-worker broke up with their girlfriend/boyfriend.
Should you mention it to them? Should you ask them if they are doing, OK?
I’m not sure, but it’s better to be safe than sorry.
For that reason, we can use today’s idiom and say, let sleeping dogs lie.
Or imagine this. Your better half comes home from work in a terrible mood.
Should you ask them what happened? It may be a good decision to not bring up the topic at the moment.