Unsubscribe or opt individual Contact out of Marketing Emails in HubSpot

Those users who have Marketing access permission can unsubscribe an individual contact from all marketing emails on their contact record.

To opt-out a list of contacts from receiving future marketing emails, import them in an opt-out list. 

• Go to Contacts > Contacts in your HubSpot account.
• Click the contact name.
• Click the dropdown Actions and select Opt-out of email.
• Choose Yes, opt them out to confirm that you want to perform this action. That contact will now be opted out of all future emails from your account.