How can I hide specific products from my website's search bar?

[greentouch]

Hi Community, 

I need your help. 

I use the theme ENTREPRISE and i'm looking for a solution to hide some products on my internal Search Bar. 

I want to keep my SEO, theses products should just not appear when a user searches for them from the search bar on my website. I can enter a specific tag (or metafield) to isolate the products concerned. Thank's a lot for your help. 
Matthieu