fight off
To push back or defend against someone or something that is advancing. A noun or pronoun can be used between "fight" and "off." What is the best way to fight off an attacker? If you feel like you're getting a cold, these vitamin C tablets should help you to fight it off.
fight someone or something off
to repel an attack from someone or something. We fought the enemy attack off, but they returned almost immediately. She fought off the mosquitoes all evening. Jed fought the attacker off.
fight off
Defend against, drive back, as in I've been fighting off a cold all week. This figurative use of the term, originally meaning "to repel an enemy" dates from the early 1800s.
fight off
v. To defend against or drive back someone or something, such as a hostile force or an infection: The enemy is advancing, but the troops will fight them off. The doctor told me to rest so I can fight off this cold.