Short and sweet. It’s spelled not Kwijibo as listed on Yoyoexpert or any of the search results for Kwijibo. It’s Kwyjibo, with a Y. It came to be from an episode of The Simpson’s where Bart fakes an IQ test. In the episode he attempts to use the word Kwyjibo. Bart says he got 22 points on a triple word score and 50 for making an 8 letter word, and that he wins and goes to leave but Homer does not allow him to leave until he defines the word.
Bart’s reply is “A big, dumb, balding, North American ape with no chin…” Homer is eating a banana so it is in reference to him. Homer (even though he is dumb) realizes the relation and chases after Bart, where Bart repeats “Kwyjibo on the loose!!”
A neat fact is that Kwyjibo at the best place on the board can net you 152 points. Wow!
So please use the correct spelling. However, if you do not that’s fine too.