defend someone or something against someone or something
1. to stand against an attack; to provide a defense against attack. Don't worry, I will defend you against any muggers. We defended ourselves against the attack. The army defended the town against the enemy soldiers.
2. . to advocate the cause of someone or something against someone or something else. The lawyer defended her against the plaintiff. She defended the company against the suit.
defend someone with something
to repel danger from someone with something. Here, defend yourself with this club. Mary defended herself with karate.