Even if this is a pretty common and easy trophy to obtain, because you can go through the entire game without ever picking up a world weapon, it is missable
What you need to do for each of the five world weapons is to pick them up with
and that's it; you don't even need to use the item for it to count. However, to be on the safe side, I'd use each weapon at least once to kill an enemy or two. Once you have the fifth weapon, the trophy should pop. Each of the weapons shine in the game so you shouldn't have a problem getting them.
The types of the weapons, and their locations where they are first found, are detailed below:
--Sword: Chapter 1. Right after coming out of the undergroudn tunnel
--Club: Chapter 5. Middle of the path at the beginning of the level. Grab this one as soon as you can.
--Javelin: Chapter 5. Once you defeat two Juggernauts, you will cross over to a roof using a rope. It's on the first of these buildings.
--Sling: Chapter 5. Right after the minotaur fight. Grab this one as soon as you can.
--Shield: Chapter 7. Easy enough because you will come across a shielf user. You will need to disarm him (
) before you can grab the shield.
These are the first places where you can find each of these world weapons. Some of them become rarer later on in the game so it's best to pick them up when you first notice them, but if you miss them the first time around you can usually find them again later on. I've highlighted the two that I found to be the hardest to come across, the club and the sling.
Hope this list should help but let me know if any additions need to be made as I'm more than happy to fix it. Happy hunting!