When you hide titles from your viewing activity:
They won't appear in Netflix as a TV show or movie you've watched.
They won't be used to make recommendations to you, unless you watch them again.
They'll be removed 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 the hide icon next to the episode or title you want to hide. If you hide 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 can't be hidden if the Activity page is reached from a Netflix Kids profile.