The phrase ‘fight fire with fire’ means to use the same tactics or weapons as the enemy when engaging in combat or verbal arguments.  It is often used to show that someone is responding to an attack by using a similar method as the attacker to fight them. The origin of this phrase is related to the literal practice of fighting fire with fire, which means to use controlled fires to stop the spread of wildfires. 

Here are some examples of how to use ‘fight fire with fire’ in sentences:

• He decided to fight fire with fire and spread some rumours about his rival to ruin his reputation.

• She was tired of being bullied by her classmates, so she fought fire with fire and stood up to them.

• They had to fight fire with fire when they were attacked by hackers. They hired their own hackers to counterattack.

• He knew he couldn’t win the debate with logic, so he fought fire with fire and used emotional appeals.

• She didn’t want to fight fire with fire, but she had no choice. She had to defend herself from his accusations.

I hope this explanation helps you to understand the meaning and usage of ‘fight fire with fire’.