Foe (noun)

1. An enemy or opponent in a conflict or contest.
2. A person with whom one has a rivalry, disagreement, or enmity.

Origin:

Old english fāh "enemy, hostile", of germanic origin; related to dutch vijand and german feind.

Examples:

1. He saw the other team as his foess.
2. The two companies were fierce foess in the marketplace.
3. She had many foess in her career.
4. He had a long-standing feud with his foe.
5. They were bitter foess for many years.