How can I remove another gab user from following me?
There are two methods:
1) If you received a notification/comment/reply from them, click/tap the 3 dots in the post box. Find the 'block' option to block the user.
If it's a reply, the 3 dots are directly under the comment.
or-
2) if they haven't posted, but are following you, go to their home page timeline, by click/tapping on their avatar. Click/tap the 3 dots under their banner & select 'block'.
Blocking - removes their post content from your view and they can't see your content.
Additionally, it will remove them from following you. This action is reversible, if you change your mind later.
Muting - removes their post content from your view, but they will continue to follow you and be able to view your content. This action is reversible.
Reporting - If you feel that a post has broken Gab's policies, you can also report any posts to gab moderators for further review.
Use the same 3 dots - select "report", then select block.
Gab's ToS (Terms of Service)
https://gab.com/about/tos