The true origin of "taradiddle" is unknown, but that doesn't mean you won't encounter a lot of balderdash about its history. Some folks try to connect it to the verb "diddle" (meaning "to cheat"), but that hasn’t been proven and may turn out to be poppycock . You may hear some tommyrot about it coming from the Old English verb "didrian," which meant "to deceive," but that couldn’t be true unless "didrian" was somehow suddenly revived after eight or nine centuries of disuse. No one even knows when "taradiddle" was first used. It must have been long before it showed up in a 1796 dictionary of colloquial speech (where it was defined as a synonym of "fib"), but if we claimed we knew who said it first, we’d be dishing out pure applesauce .

Examples

"Even parents with the very best of intentions find themselves telling taradiddles to their offspring." - From a blog post by Ben Schott at nytimes.com, November 12, 2010

"As truths go, the history of Miss Rossiter she had laid out was unimpressive: a forked-tongue taraddidle of the highest order and if I were to serve it up to Hardy and be found out afterwards I should be lucky to escape arrest, if not a smack on the legs with a hairbrush for the cheek of it." - From Catriona McPherson's 2009 novel Danny Gilver and the Proper Treatment of Bloodstains