How to hide your posts from someone on instagram?

The most straightforward way is to block them. This action hides your entire profile, posts, and stories from that specific person. They simply won't be able to find you. If your account is set to private, you also have the option of removing them as a follower. It's worth noting you can hide just your stories from individuals in your settings, but this won't affect your main feed posts. Blocking is the only guaranteed method for everything.