The term 'THAT REALLY HURTS!' can be summarized with the crossword solution YOWIE, which is a five-letter word. YOWIE is an Australian Aboriginal mythological creature, similar to Bigfoot or the Yeti, that is said to inhabit the Australian wilderness. It is often described as a large, hairy, ape-like creature that makes loud noises and is capable of causing great fear and pain. Thus, the crossword solution YOWIE is an appropriate summary for the phrase 'THAT REALLY HURTS!'