You will still be able to see their posts, but you will not get any notifications of their posts.
For example, if MutedMember makes a post in Interesting Topic that @ mentions you, you will not get a Notification that they @ mentioned you. But if you later go to Interesting Topic and read it, you can choose to read or not read the post. Muting a member does not remove all evidence of their existence on the forum. In other words, it’s kind of like you can go to them but they won’t go to you.