1. Athletic Ability
6. Defense - another team or individual can prevent you from accomplishing your goal.
In addition, a "sport" should not be judged, like in diving, gymnastics or figure skating, and one's ability in the activity should not be enhanced by the consumption of alcohol.
If an activity doesn't qualify as a "sport", it can fall into 3 other categories:
Athletic competitions: i.e. 100 meter dash, pole vault, swimming and bicycle racing.
Athletic events: i.e. diving, gymnastics, figure skating and sycronized swimming. Usually involves "impartial" judges that determing the winner. Note: judges are not equivalent to umpires or referees.
Games: Chess, bowling, golf, poker and curling.
So what's your stance? What makes a "sport" a sport?