Hidden Subjects are the subjects that you wish to hide from the teaching skills subject list found in the Update Skills panel when editing a Tutor’s teaching skills. To hide subjects, head to System > Settings > People and Activity > Hidden Subjects, which will open the Hide Subjects menu.
In cases where you wish to prevent a subject from the teaching skills subject list (found within the ‘Update Skills’ panel when editing a Tutor’s teaching skills), you can hide these by heading to System > Settings > People and Activity > Hidden Subjects. Navigating here will open the ‘Hide Subjects’ panel, from where you can enable different subject’s checkboxes to hide them from the teaching skills subject list.