Feedback information provides broader term, narrower term, and related term information for a specified query with a context index. You obtain this information programatically with the CTX_QUERY.HFEEDBACK procedure.
Broader term, narrower term, and related term information is useful for suggesting other query terms to the user in your query application.
The feedback information returned is obtained from the knowledge base and contains only those terms that are also in the index. This increases the chances that terms returned from HFEEDBACK produce hits over the currently indexed document set.
Oracle Text Reference for more information about using CTX_QUERY.HFEEDBACK