oppose in WordNet English dictionary

1. be resistant to
   "The board opposed his motion"
   oppose  controvert  contradict 
   
2. contrast with equal weight or force
   oppose  counterbalance 
   
3. fight against or resist strongly
   "The senator said he would oppose the bill"; "Don't fight it!"
   fight  oppose  fight back  fight down  defend 
   
4. set into opposition or rivalry
   "let them match their best athletes against ours"; "pit a chess player against the Russian champion"; "He plays his two children off against each other"
   pit  oppose  match  play off 
   
5. be against; express opposition to
   "We oppose the ban on abortion"
   oppose 
   
6. act against or in opposition to
   "She reacts negatively to everything I say"
   react  oppose