competitor

noun

1. A person or organization against whom one is competing.

   “Hitherto the river had given facilities to Kingston traders which their competitors elsewhere could not possess, but now the railway took the malt from distant towns to the London market at lower rates than the bargemasters.”

2. A participant in a competition, especially in athletics.
3. (obsolete)Partner, associate, one working with another toward a common goal.

   “Ioine with me now in this my meane eſtate, […] And when my name and honor ſhall be ſpread, As far as Boreas claps his braſen wings, Or faire Botëes ſends his cheerefull light. Then ſhalt thou be Competitor with me, And ſit with Tamburlaine in all his maieſtie.”