From the Manager Tools newsletter:

“We think one of the best definitions we’ve ever heard for professional is someone who does what they’re supposed to do, when they’re supposed to do it, whether they want to or not, without debate.

And the simplest measure of professional discipline is sticking to your calendar and accomplishing your deliverables in a timely fashion.

Profoundly powerful, yet ever so rare.”

This is so similar to the Nil Eyar’s assessment for being indistractable:

“Did I do what I said I was going to do, for as long as I said I was going to, without distraction?”

It seems the professionals are indistractable.