Normally it´s a friendly word.

In the example in the dictionary is: Look, XXXXXX, you are annoying me. You could use pal, friend, buddy, your friend´s name, etc in this sentence. You are telling your friend (or a stranger) that they are bothering you.

It's more of an American word but of course, it's understood everywhere. It means 'friend' or 'buddy' but in the UK that second usage is more prevalent. It's a subtle way of insulting someone lol. People sometimes do the same thing with 'buddy' here. The context would make it obvious. As an example of what I'm referring to: Look, pal, I don't care what you think... Listen, buddy, you don't have a clue what you're talking about... The surrounding words make it pretty clear that the person in question is not their pal. The tone of voice would make it clear too.

Hey there, Guille. I am from California, in the US, and I haven't heard people use "pal" to refer to an annoying person. Cambridge books, however, are British publications, so I imagine it must be used that way in the UK. To answer your question, you can tell the difference by the context. For example, if someone is speaking with a sarcastic tone, they problem mean 'annoying person', but if they sound genuine, they likely mean 'friend'.