If asked what the riddle is, the skeleton will recite it:
"Think of words which end in '-GRY'. Angry and hungry are two of them. There are but three words in the Common Tongue... what is the third word? The word is something that one uses everyday. If thou hast listened carefully, I have already told thee what it is."
If TNO doesn't have 18 intelligence, but has at least 17, he can solve this riddle directly at its source, with the nearby Riddling Skeleton.