Possible Mishearings/Misspellings:
* Bad John: This could be a name, or a slang term for a person who is considered "bad" or undesirable.
* Bad Jon: Similar to "Bad John", but with a slightly different name.
* Bad Hombre: This is a Spanish term meaning "bad man" that was used in US politics.
Context is Key:
To accurately understand what "badjohn" means, you need to consider the context in which you heard or read it.
Please provide more context:
* Where did you hear/read this term?
* What was the surrounding conversation or text?
* Who used the term?
With more context, I can help you understand the intended meaning of "badjohn".