When you hide titles from your viewing activity, they won't appear in Netflix as a movie or TV show you have watched. They won't be used to make recommendations to you unless you watch them again. Hiding titles from viewing activity will also remove them from the Continue Watching row.
To hide titles from your viewing activity:
From a web browser, go to your Account page.
Open Profile & Parental Controls for the profile you want to update.
Open Viewing Activity for that profile.
On the Activity page, click on the icon next to the episode or title you want to hide. If you are hiding an episode, you'll see the option to hide the entire series.
To hide all of your viewing activity, select the Hide all option at the bottom of the page and confirm.
It can take up to 24 hours for a hidden title to be removed from all your devices. Titles cannot be hidden if the Activity page is accessed from a Netflix Kids profile.