We use this expression to say that something is not very good.
You can use this phrase in ………… language.
A: That’s a nice looking phone. Is it a smart phone?
B: Yes, but it’s not up to much. I’m going to get a new one soon.
A: Let’s go and see Sherlock Holmes.
B: A friend told me it’s not up to much. Why don’t we see that new thriller instead?