"Boodle" is one of those words that definitely sounds made up (well, technically all words are made up, but you know what I mean). I assure you though, it is a very real word, and one that has quite a few meanings. In the early 1800s, when it first started to be used, "boodle" referred to a group of people. It later evolved to mean a large amount of money, often obtained through illicit means (Webster's). Those seem similar enough; they both have to do with a big collection of something.
When you look up "boodle" in Webster's Unabridged Dictionary, there are even more definitions listed, including "counterfeit money," "bribe money," and "plunder or swag of any sort." The term can even be used as a verb meaning "to obtain money through bribery or swindling." And then there's a "boodle fight," which is the military practice of eating a meal in Filipino culture. As you can see, it is a very versatile word.
If you're thinking that the word boodle sounds familiar but can't quite figure out why, it's probably because you've heard it used as part of the idiom "the whole kit and caboodle." Never heard of it, or want to learn a little bit about the history of the phrase? Keep reading! (You may know the term from the popular organizer cases named Caboodle as well, which are great, but we won't talk about those here.)
The Whole Kit and Caboodle
This fairly well known idiom means the entirety of a group of people or things. The original phrase was just "kit and boodle," but it meant the same thing as it does today. The saying combines two words that both mean a collection of objects (which makes it a bit redundant, but idioms never make perfect literal sense anyway). Other variations of the phrase included "the whole boodle," "the whole caboodle," and "the whole kit and cargo" (The Word Detective).
Let's look at the first word. "Kit" is a term that predates "boodle" and refers to a soldier's kit, a bag that contained everything a soldier might need on the battlefield back in the 1700s (The Word Detective). Of course, we still use the word "kit" today to refer to any kind of collection of items or tools that pertain to a specific job—think a first aid kit, a plumber's kit, etc.
As we've established above, "boodle" refers to a collection of items or people. While the first known use of "boodle" is listed by Merriam-Webster as being in 1928, the term "caboodle" didn't become popular for another ten or fifteen years. It doesn't have a significantly different meaning than its root word, so they could be used as synonyms. The prefix ca- (sometimes seen as ka-) was most likely added for alliteration purposes, and is probably the reason that this variation is the one that survived to present day.
I hope you enjoyed learning more about this word and idiom! I know I'm definitely going to start trying to incorporate "boodle" into my vocabulary more. It's such a fun word!
References:
The Word Detective. 2011. "Kit and Caboodle." August 15, 2011. http://www.word-detective.com/2011/08/kit-and-caboodle.
Webster's Third New International Dictionary, Unabridged, s.v. “boodle.” Accessed December 11, 2020. https://unabridged.merriam-webster.com.