1 : to fight in order to keep (someone or something) safe : to not allow a person or thing to hurt, damage, or destroy (someone or something) [+ obj] ▪ We are prepared to defend [=protect, guard] our country. —often + from or against ▪ They have every right to defend themselves from those who would hurt them. ▪ The army defended the territory against invaders. ▪ Her body was no longer able to defend itself against disease. [no obj] —usually + against ▪ These new weapons will make us better able to defend against attack. ▪ The body's immune system defends against illness.
2 [+ obj] : to fight or work hard in order to keep (something, such as a right, interest, cause, etc.) from being taken away ▪ The group defends [=protects] the rights of the poor. ▪ The company must defend its own interests.
3 [+ obj] : to speak or write in support of (someone or something that is being challenged or criticized) ▪ As a U.S. senator, it is my responsibility to defend [=uphold] the Constitution. ▪ We believed it was a cause worth defending. ▪ She defended her friend's behavior. ▪ Stop defending him. What he did was wrong.
4 sports : to try to stop opponents from scoring [+ obj] ▪ Your job is to defend the goal. ▪ Focus on defending the basket. [no obj] ▪ He defended well throughout the game. —often + against ▪ She tried to defend against the jump shot.
5 [+ obj] : to compete in order to try to keep (a title, championship, etc.) ▪ The team is looking to defend its national title. [=to win the national title again] ▪ She successfully defended her championship. [=she won the championship again]
6 [+ obj] : to work as a lawyer for (someone who is being sued or accused of a crime) ▪ They hired a famous lawyer to defend their son. ▪ She defended herself during her trial.