@Arexiou, no, not necessarily, because now the advice and explanations start flowing in(just look at what idiotic things I wrote below!)
So,Genkudo, here's what you do to end your thread, depending on what thread it is, there're different ways of going about this:
The regular answer would be that you can't, only if you're a premium member or a mod/admin, can you do so. That is if we're talking about removing the thread completely.
But if we're talking the 'I want to post something that'll make others stop posting', then listen here man!
First off, do not start trolling or flaming, that will only encourage the other members to:
-include sentences in their posts explaining what a douche you are or,
-they'll include pictures(usually some kind of meme)
this one for example:
You must be registered for see images
or,
-just write something close to what is written in the picture above.
Secondly
Writing something like 'Please don't post in this thread(anymore)' could help, but it's not guaranteed, because some might just post again saying 'ok =DD', or simply ignore youU_U
Lastly(I know there's more, but I've kinda lost interest in writing much more, so yah)
Write something reeeeeaaaaaaally cheesy/corny, that'll keep most ppl away, for sure! Either that or you just write something that makes no sense, you'll get close to no answers in those threads and they die as well as become forgotten rather quickly.