How can I block a worklog time if the original estimate field is empty?

[climba]

I would like the system locked the worklog hours in user task if the original field was empty estimated. How can I do this?

[Nic Brough -Adaptavist-]

You probably need https://developer.atlassian.com/display/JIRADEV/Customizing+Text which will let you rename system concepts like "assign" or "priority"