In the episode of Friends, "The One With All The Embryos," Ross asks Monica and Rachel, "What is Chandler Bing's job?" which stumps the women. Rachel tries to reason it out, and blurts out, "HE'S A TRANSPONSTER!", to which Monica responds, "THAT'S NOT EVEN A WORD!"
Because nobody knows Chandler Bing's job, it has since become accepted that anybody who won't reveal what they do for a living is a Transponster, such as Ed The K Motley.