Definition:
Humorous- funny and comical.


Example:
“No matter how much Aunt Petunia wailed that Dudley was big-boned, and that his poundage was really puppy fat, and that he was a growing boy who needed plenty of food, the fact remained that the school outfitters didn’t stock knickerbockers big enough for him anymore. The school nurse had seen what Aunt Petunia’s eyes… simply refused to see: that far from needing extra nourishment, Dudley had reached roughly the size and weight of a young killer whale.”
Harry Potter and the Goblet of Fire, by J.K. Rowling


Explanation:
This is just humor for humor’s sake. Rowling does not regard the situation as very serious, nor is she making a satirical attack on Dudley. She is merely creating a character that is very humorous to the reader. In particular, she is using comic exaggeration, with “roughly the size and weight of a young killer whale” being a little larger than you might normally expect a kid to be.