For me, it’s not “do what you feel like doing,” because that’s unlikely to be useful.
You might feel like hanging out on the beach, telling off your boss or generally making nothing of much value. Authenticity as an impulse is hardly something to aspire to.
It’s not, “say whatever is on your mind,” either.
Instead, I define it as “consistent emotional labor.”
We call a brand or a person authentic when they’re consistent, when they act the same way whether or not someone is looking. Someone is authentic when their actions are in alignment with what they promise.
Showing up as a pro.
Even when you don’t feel like it.
Especially when you don’t.