Delete a Data Extension
If you don’t need the information that’s stored in a data extension, you can delete it. When you delete a data extension, the information that it contains is also deleted and can't be accessed anymore.
Marketing Cloud Engagement temporarily retains information from a deleted data extension to ensure that current processes can access that information. During this period, you can’t create a data extension with the same name as the deleted data extension.
Don’t delete a data extension that’s assigned to a triggered send definition. If you do, the status of the triggered send definition changes to indicate an error.
You can’t delete a data extension if it has a data relationship to contact records or to another data extension. To delete a data extension that has a data relationship, first use Data Designer to remove the relationship, and then delete the data extension. See Data Designer in Salesforce Help.