I have seen others. We've tried to do our best based on what we've read. Nevertheless, I would suggest you improve it. So as to reassure the public, I'd be willing to add to the definition by saying “as part of independent or paid work”. This would further highlight the fact that the journalist must be a member of a media company, and not just someone who suddenly calls himself a journalist so as to defame someone or spread a falsehood all the while claiming he has a secret source.
In any event, any journalist with a secret source is civilly liable. Any such individual is also criminally liable should he or she engage in libel. The journalist can't use the excuse that he wants to keep a source secret. I want to protect individuals who may end up doing something positive for our society. I'm referring to journalists who get information from confidential sources. I'm referring to journalists who carry out an investigation and publish it once they are in a position to submit independent proof of their source to the public. Should their source mislead them, these individuals would be liable for any damage caused to a third party as a result.