When your existing tags become obsolete (or perhaps you were a little carried away with the organization) you may find yourself wanting to delete some of your tags.

It's easy to delete a tag, maybe a little too easy, so you'll want to use this power wisely. Admins can delete tags in two places, but a word of caution: this action is permanent

Deleting Tags from Settings

To delete tags from your settings, go into Settings > Conversations > Tags. Here you can view your tags in all mailboxes or filter by a specific mailbox. 

Click the trash can icon for any tags you want to remove. 
Once you delete a tag, it will disappear from your tags list and be removed from all conversations tagged with it. 

Deleting Tags from the Manage Tags Menu

You can manage your tags directly from a conversation using the Manage tags option in the tag dropdown menu. 
Here you can edit or remove any of your tags.