When you select recipients for a marketing email, you can exclude specific contacts or lists from receiving the email.
Please note: if a contact is included as a recipient on the Individual contacts tab, they'll receive the email even if they're a member of a list you're excluding. If you don't include a contact as a recipient in the Individual contacts tab but they are a member of an inclusion list and an exclusion list that you've specified in the Lists tab, that contact will not receive the email.
Exclude contacts in the classic email editor
In your HubSpot account, navigate to Marketing > Email.