I enjoy riddles. By happenstance, I happened upon the (in)famous -gry riddle, but luckily before I got too carried away searching for an answer I found an essay written by the Word Detective on this very puzzle.
The key to successfully finding an answer to this wriddle is in getting the wording correct:
Angry and hungry are two words that end in ‘-gry’. There are three words in the English language. What is the third word? Everyone knows what it means and everyone uses it every day. Look closely and I have already given you the third word. What is it?
For the answer, see this essay.