: to disagree with or disapprove of (something or someone) : to compete against (someone) : to be an opponent of (someone)

What is the full meaning of oppose?

/ (əˈpəʊz) / verb. (tr) to fight against, counter, or resist strongly. (tr) to be hostile or antagonistic to; be against. (tr) to place or set in opposition; contrast or counterbalance.

What does it mean to oppose a decision?

You might oppose a decision if you don't agree with it or if it's the opposite of what you believe or know is right. Sometimes, though, to oppose just means to be on the other team.