How to hide and block a directory for a specific user
 

I want to create a user which only may have access to his own home directory. But more important, I want to hide and deny all rights of some specific directory's for that user, cause I don't want that user to browse trough some sensitive stuff (even the filename's in that directory's may not get known). I've searched, but couldn't find a satisfying solution for this problem.
I hope someone can help me out.

Well, this might sound a bit cruel, but...
Create a "forbidden" group for THAT user, and after that...

man chmod
man chgrp

..Will tell you what to do.

Tnx for your quick reply Tih8710.
That I have to set the permissions with chmod and chgrp I understand, the specific user already has it's own unique group, but what do you mean by creating a "forbidden" group? (And how do you create a group like that). Is that "forbidden" group restricted from viewing filename's other than its homedirectory?