to be, fight, against (a person, organization, plan, idea etc)
fight, obstruct
Cases of word usage
1) to make or oppose a claim at a law court (litigate)
2) not able to oppose the effect of a disease, chemical etc (non-resistant)
3) (the act, power, of) resisting; (in a country occupied by an enemy) a group of people organized to oppose the enemy; an opposing force (resistance)
4) to oppose or prevent (something) successfully (thwart)