What does "random" mean in the context of password creation?

Disclaimer: as you will see from my question I'm a total outsider in this subject, just very curious.

I was wondering how easy it would be to crack a password-protected RAR5 file, and I found many answers along the lines of "a truly random password would be much more difficult to crack than a password based on real words". Also, a lot of answers refer to password randomness.

I know that passwords based on real words are easily cracked by dictionary attacks and probably this is what those answers refer to, but I'm still not clear about what "random" means in the context of password creation, for the following reason.

Even if I generate a sequence of characters using the best "randomizer" ever, the chances that I get "HelloWorld" and the chances that I get f.ex. "gkwwpBnePU" are in my understanding exactly the same, so does "random" in this context mean "as distant as possible from any real word" ? But if yes, doesn't this make the password not-so-random after all ?

The thought that started my doubt - which I believe is the same concept but I'm not sure - is: if I choose a password which is a real word but from an obscure dialect of a very uncommon language whose dictionary no attackers would feed to their cracking tools, would such password still be more crackable than "gkwwpBnePU" ? (assuming of course that "gkwwpBnePU" isn't actually a real word in any language, see what I mean ? ).