fight somebody/something ↔ off phrasal verb ( see also ↑ fight )
1 . to keep someone away, or stop them doing something to you, by fighting or opposing them:
Bodyguards had to fight off the crowds.
The company managed to fight off a takeover attempt.
2 . to succeed in stopping other people getting something, and to get it for yourself:
Allan fought off stiff competition from throughout the UK to win one of only four places at the college.
3 . to try hard to get rid of something, especially an illness or a feeling:
Elaine’s fighting off a cold.