Wiktionary
knee-slapper
n. (alternative spelling of knee slapper English)
Usage examples of "knee-slapper".
Well, I told it to him, and as depressed as he was, he practically fell down laughing, so I told him to get himself a pen and paper, and once he did I sat down and told him the one about the poet and the feather merchant's twin daughters, and then the one about the Sumo wrestler and the circus thin lady, and the one about the six-fingered gangster and the one-eyed manicurist, and by the time the sun had come up I've guv him about a hundred such knee-slappers.