Usually, that means you're looking. You're open to opportunities. Because the opportunity you have right now isn't checking all of the boxes. If it were, you wouldn't be looking.
But what you're really saying is that you don't want something to pass you by. Something you couldn't turn down if it were presented to you. You're avoiding opportunity cost.
Maybe that's why millennials get such a rap for job hopping. Because another way they (we) look at avoiding opportunity cost is through something we call FOMO. We hear things and see things and feel like we are missing out on something. The truth of the matter is that we just might be missing out...
Employers are starting to do something about 'hoppiness.' They've realized that doing nothing is really, really expensive...Have you?