"You seem to have given this a great deal of thought, Moody," said Karkaroff coldly, "and a very ingenious theory it is — though of course, I heard you recently got it into your head that one of your birthday presents contained a cunningly disguised basilisk egg, and smashed it to pieces before realizing it was a carriage clock.
There are no more uses of "ingenious" in the book.
Show samples from other sources
It was an ingenious solution to the problem—as reliable as it was easy.
The first person to put wheels on a suitcase had an ingenious idea.