Consult the profile properties.
Hover over the profile property you want to delete; a cross appears.
Click on the cross to delete the profile property.
Confirm you want to delete the profile property by clicking on 'OK'.
Pay attention: you can only delete a profile property when it has not yet been used. You always have the possiblity to archive a profile property in case it is already in use. When you archive a profile property, it is pushed into the background (below all other functions), but it can still be unarchived.