fight back phrasal verb ( see also ↑ fight )
1 . to work hard to achieve or oppose something, especially in a situation where you are losing:
United fought back and scored a last-minute goal.
fight back against
She was fighting back against the cancer.
2 . to use violence or arguments against someone who has attacked you or argued with you:
The rebels are fighting back.
3 . fight something ↔ back to try hard not to have or show a feeling:
She looked away, fighting back her tears.
He fought back the impulse to slap her.