adj.
1.indicating opposition or resistance
2.characterized by antagonism or antipathy
3.arousing animosity or hostility
4.used especially of drugs or muscles that counteract or neutralize each other's effect
5.opposing or neutralizing or mitigating an effect by contrary action
6.incapable of harmonious association
Idiom of the Day
have (something) against (someone or something)
to dislike someone or something
I do not know why but my teacher seems to have something against me.