Yes, agreed on your definition, probably should have been more specific (E.g. Without the ball). However, to elaborate on this, when the fielder does not have the ball, and the base is obstructed such that a slide can not get you completely to the base, or if you did, your leg would get caught up with the fielder, what is your suggestion? Stop? Slide short of the base? Go around the player? Run into them without malicious intent.
I will tell you in baseball, that at second base the fielder will be taken out with a slide typically (E.g. "Breaking up a double play") whether they have the ball or not, and at home plate there could likely be a collision.