I want to buy an CS:GO Item on steam from an account which doesn't have the game CS:GO. My library has no games. I will be trading/gifting/selling the items afterwards that I buy, but I also have plans to buy CS:GO in my account. So is it possible buy the items without the game?
Yes you can buy games or items, without previous games installed.
For games you buy them as gifts and choose add to inventory as your option,
For steam community items like dota2, tf2 and csgo items they will always be saved to your inventory so you don't need the game in your library
Sidenote(if you buy tf2/dota crates you will need the game to open them)