Yes, you can manually unsubscribe a contact from a list. However, you cannot revert this action.
To manually unsubscribe a contact from a list follow these steps:
From your Contacts click the list you would like to unsubscribe a contact from.
Click the Options Arrow from the contact you’d like to unsubscribe and then click 'Unsubscribe from this list'.
...
the checkbox next to the name of the contact
New options will appear in the right corner. Click on “Unsubscribe from all lists” and then confirm.
...