"Oh, come off it!" said Edmund, who was tired and pretending not to be tired, which always made him bad-tempered.
(Giants of any sort are now so rare in England and so few giants are good-tempered that ten to one you have never seen a giant when his face is beaming.
There are no more uses of "tempered" in the book.
Show samples from other sources
If you had only given me some hint, if you had only broken your word with me a couple of times, if you had been bad-tempered or impatient with me—if you had been a lesser man, maybe I could have taken what I saw you doing.
Harper Lee -- Go Set a Watchman
For the rest of the day, I’m short-tempered and distracted.