defend in WordNet English dictionary

1. protect or fight for as a champion
   champion  defend 
   
2. argue or speak in defense of
   "She supported the motion to strike"
   defend  support  fend for 
   
3. state or assert
   "He maintained his innocence"
   maintain  defend 
   
4. be on the defensive; act against an attack
   defend 
   
5. protect against a challenge or attack
   "Hold that position behind the trees!"; "Hold the bridge against the enemy's attacks"
   defend  guard  hold 
   
6. fight against or resist strongly
   "The senator said he would oppose the bill"; "Don't fight it!"
   fight  oppose  fight back  fight down  defend 
   
7. be the defense counsel for someone in a trial
   "Ms. Smith will represent the defendant"
   defend  represent