Great question. These tongue terms can get confusing.
Rough: Looks dry. This occurs during the peak of an acute EPF/EPI where it has damaged the body’s fluids.
Tender: Looks tender – possibly swollen, and may have some cracking on the edges that look like the baleen of a whale. Indicates Qi Deficiency. In chronic stage of disease, it can indicate Cold syndrome.
Protruding: The tongue sticks out of the mouth at rest. Seen in dementia.
Waggling: The tongue is wagging back and forth quickly. Often seen in high fever, or a blood disease due to bacteria or virus.
Waxing: Thin coating changes to thick, meaning the disease is waxing (getting worse)
Waning: Thick coating changes to thin, meaning the disease is waning (getting better)