Competent and able to handle everyday tasks with ease.

For anything considered complex, able to give a good start and potentially work a partial solution (for running, they can do a good half-marathon without too much trouble).

Not a world-beater, not someone who can handle any task trivially, but someone who can definitely contribute to even expert/Ph.D level fields, if only at at a lower level (ie doing tasks at the direction of the lead researcher/engineer).

If they're "really good", I expect all that, and that they can self-lead for complex tasks, with the potential to grow into the latter role of "lead".

I am, at my worst, "really-good" at a lot of things, but I've also met a few rare people who make me feel like I'm in that half-marathon while they're doing a 100m dash, and they just never slow down. That's rarely a question of skill or competence for me, it's more focus and dedication to a single task.