Hi, Dan! Unfortunately, we’re not adding any more entries to the online version of this thesaurus because we’re in the process of drafting the print version, which should be out in the spring (yay!). Right now, we don’t have plans for a Rapids entry; we’re trying to include a lot of different settings, and since we already have a river, a creek, and a waterfall, we probably won’t have room to add another river-related entry. But a wild river is a strong setting ripe with opportunities for conflict, so we’ll make sure to incorporate some wild river description into the River entry. Thanks so much for the suggestion!