How much of an expert do you have to be to be an expert?

Broadsheet asks its readers what they're experts in.

But how much of an expert do you have to be to claim to be an expert? Because I know more stuff than most people about quite a number of things, but in all these areas there are people whose expertise exceeds mine by several orders of magnitude and anyone with knowledge of the field would laugh in my face if I claim to be an expert.

I do perfectly decent translations with the occasional flicker of genius (note to clients: I cannot guarantee that one of these flickers of genius will end up in your text) which is all very impressive to non-translators, but within the profession I am unremarkable and to claim to be an expert in translation would be bordering on fraud

I can explain to you how a mistranslation or a misunderstanding happened in any combination of the languages I've studied, but any academic in any of these languages would completely reject anything I might have to say.

If you've never read Harry Potter, I can explain to you anything about the plot or the characters or the rules of the universe, and if you give me 30 seconds on google I can produce multiple citations. But I'm not nearly good enough to work for Leaky.

In fact, in any of my fandoms, I'm a total geek to outsiders and a complete poseur to fen.

People are always asking me to google up stuff for them because apparently I can do it better than them, but librarians would scoff at my measly research skills.

So I may well be able to pass myself off as an expert in translation, or comparative linguistics, or Harry Potter or Monty Python or Star Trek, or internet research, or even things like music theory or music history or make-up or Toronto or Canadian children's television of the 1980s, but I don't dare publicly say I'm an expert in any of these things, because the real experts are lightyears beyond me.