1) a person trained for competing in physical exercises and outdoor games e.g. a person who is good at running, jumping, swimming etc (athlete)
2) the act of competing (competition)
3) to stop taking part, competing etc (drop-out)
4) competing (with); to be as good as (another person, thing) (rival)
enjoying, engaged in, competition
willing to oppose
competing (with); to be as good as (another person, thing)
opposing