Wordpress is actually a CMS, so I guess it could replace Dreamweaver for you in a way but it doesn’t work the same. WordPress adds some tables to your database so it can save the content you put into it. Where as Dreamweaver is a program locally that generates static HTML files. WordPress lives on your server. So when you would want to add/change stuff on your website you would simply login to the admin panel of WordPress and make changes. You will be eliminating the step of making the changes locally in Dreamweaver and uploading the new files.
As you can see this is a bit more of a complicated topic. I would recommend reading up on WordPress and making sure its the solution you need for your project.