Lightroom remembers old keywords and suggests them as search terms

I have recently reorganised my keyword terms but Lightroom still suggests old terms that are no longer in use when typing in the search box. I have even deleted the entire cloud library but it is still suggesting old keywords as search terms. Some of the new and old keywords are similar so it is easy to select the wrong one from Lightroom's suggestions and then return no results. Is there a way to purge all of these keyword terms and start from scratch?