Here's why the question is tricky:
* Dictionaries are not comprehensive: They aim to include the most common and widely used words, but it's impossible to capture every single word ever created or used.
* New words are constantly being added: Think of slang, technical terms, and words coined online. Dictionaries strive to keep up with this ever-changing landscape.
* Words fall out of use: Language evolves, and words can become obsolete. These might disappear from dictionaries over time.
So, the question is more of a thought experiment about the nature of dictionaries and the ever-changing nature of language. There's no single word that was intentionally left out!