Publishing is a dynamic field, and though a generally accepted (and understood) terminology exists, there's no Great Publishing Dictionary in the Sky where definitions are chiseled in stone. Thus, I can say (as I often do) that the term "traditional publisher" has no accepted industry meaning--that it is, in fact, an intentionally spurious label invented by one of the more notorious author mills--but I can't point to any definitive proof, or cite any recognized authority to support my statement.
Ditto for my currrent pet peeve, "legitimate agent."
Unlike "traditional publisher," "legitimate agent" wasn't always a meaningless term. Way back in the dark ages, when Writer Beware was first getting off the ground (okay, 1998), it was generally understood to denote an agent with standing in the industry--i.e., an agent who was reputable, experienced, and successful. Over the past few years, however, I'm seeing the term used more and more often to describe an agent who is merely well-intentioned, responsive, and non-fee-charging. Have you heard of Brand New Agent? someone will ask on a writers' message board. Yes, she doesn't charge a fee and she responded to my query in less than a week, someone else will reply. Oh good, the original questioner will say, without asking whether Brand New Agent has any relevant professional experience or whether she has ever sold a book. Looks like she's legit.
Why is this a problem? Because while it's great for an agent to be well-intentioned, responsive, and non-fee-charging, that doesn't necessarily mean the agent is reputable, experienced, and successful. Good intentions don't sell books, after all; promptness doesn't necessarily imply expertise, and not charging a fee, while commendable, says nothing about an agent's skill. (Here are some more thoughts on why skill is important.) Since you can no longer be sure, when someone says "legit," which set of descriptors they intend to invoke, "legitimate agent" has become as useless a term as "traditional publisher."
What I prefer:
- Reputable agent. An agent with a good standing in the publishing industry, i.e., a track record of commercial sales.
- Experienced agent. An agent with publishing industry experience, i.e., someone with the professional background to know what s/he is doing, as demonstrated by a track record of commercial sales.
- Successful agent. An agent who has sold, and is actively selling, books, i.e....someone with a track record of commercial sales.
Again, of course, there's no Great Publishing Dictionary in the Sky. So I can't claim any authority for my preferred terms, other than the fact that I think they are more useful. Nor can I assume that others will understand them in the same way I do--which is why I always try to pair a word like "reputable" with concrete information about the agent's clients and sales.
The point is that language is imprecise. Professional experience and achievement are far less ambiguous. Don't rely on terminology; always check the facts. And remember the Writer Beware mantra: Track record (or, if the agent is new, relevant professional background) is the bottom line.