Sure, but it doesn't sound as good does it, doesn't roll off the tongue quite as well. I think that is what you would call an idiom. I love Idioms.
Just thinking about the co-conspirator thing. I'm thinking, you can call someone a worker and it defines that they work, you can call someone a conspirator and it defines they conspire. By calling them a co-worker you define they work with the subject, by calling them a co-conspirator etc etc