A target segment is just a set of rules, conditions, or criteria that you define to shortlist the guests who qualify the rules.
Important: Deleting a target segment does not impact the past campaigns in which the target segment was used.
Before you begin, ensure you have the Delete permission for target segments (Admin > Security Roles > Marketing Manager > Permissions > Marketing Manager > TargetSegment > Delete).
At the organization level, click the Marketing icon and navigate to Segmentation > Target Segments.
Click the name of a segment you want to delete.
On the Edit Target Segment page, click Delete.

The target segment is deleted permanently.
Note: The Delete button is disabled for a target segment created from smart marketing.