To oppose something means to disagree with it or try to stop it from happening.
When we think of opposing something, we might imagine a protest or a debate where people express their disagreement. But the word "oppose" is often used in more subtle ways too. For example, if you're voting for someone, and they take a stance that goes against what you believe, you could say that you oppose their policy. Or, if you disagree with a friend's decision to move away, but don't want to ruin the friendship by being overly critical, you might say that you oppose the idea of them leaving.
In everyday life, opposing something can be as simple as saying no to a suggestion or expressing your doubts about an idea. You might oppose a new rule at work because you think it's unfair, or oppose a friend's plan to travel because you don't feel safe in the area they're visiting. The key thing is that when you oppose something, you're not just stating your opinion - you're also showing that you care about what's happening and want to make your voice heard.
To attempt to stop the progression of; to resist or antagonize by physical means, or by arguments, etc.; to contend against.
Example: to oppose the king in battle
