Summary
My installations get cluttered with workflow copies and backups that are difficult to delete from the UI. They are inactive and it takes many clicks to get rid of these. Here is a quicker way with JCLI and the renderRequest action.
Details
Just substitute in the workflow name below, but make sure it is url encoded first:
--action renderRequest --file "" --request /secure/admin/workflows/DeleteWorkflow.jspa --requestParameters "confirmedDelete=true&workflowName=<<<name of workflow>>>"