A Suppression list is a list where you should include the members of your list that you never want to be added to it again and to never send them any of your future newsletters. Keep in mind that, after moving said members to this list, you won't be able to ever add them to any of your mailing lists in the future. This way, you adjust your mailing lists to your liking and create even more targeted campaigns.
Please note that through this function, you can choose whether to permanently delete these members even from your Suppression List or keep them there for historical or demographical reasons.
You can find your Suppression List by clicking on the Settings icon on the right top corner of your Moosend Account and then by choosing the Suppression List option on the menu appearing.
Once inside your Suppression List, you can view all the members that you have manually added to it.