Here's how the meaning of "con" has evolved:
* "Con" can be a prefix meaning "with", "together", or "jointly", like in "congregate" (gather together) or "concurrent" (happening at the same time).
* "Con" can also stand for "against" or "opposed to", like in "contradict" or "contrary". This meaning comes from the idea of opposing something together or jointly.
* "Con" can also be used as a slang term for "to deceive", like in "con man" or "confidence trick". This meaning evolved from the idea of working with someone to deceive them, often using a confidence game.
So, while the root meaning is "with" or "together", the meaning of "con" can vary depending on the context.