How do you feel, Georgie?"whispered Mrs. Weasley.George's fingers groped for the side of his head."Saintlike,"he murmured."What's wrong with him?"croaked Fred, looking terrified. "Is his mind affected?""Saintlike,"repeated George, opening his eyes and looking up at his brother. "You see...I'm HOLEY, Fred, geddit?

”

In this quote, George has just been injured and is responding to Mrs. Weasley’s question about how he is feeling. He is trying to make a joke about his injury, saying that he is “holey,” hinting that he must have encountered a situation in which something was able to make physical holes in his body. Fred is horrified, thinking that George’s mind has been affected. George then clarifies that he meant what he said literally and was making a pun on the fact that he is now “holey.”