Against means in opposition to something, or in contact with a surface.

When you're against an idea, you disagree with it or think it's wrong. A student might argue against having homework on weekends, explaining why they believe it's unfair. Two teams play against each other in a soccer match, competing to see who wins. The word captures that sense of opposition: being on the opposite side of a conflict, debate, or competition.

The word also describes physical contact or position. You might lean against a wall while waiting for class to start, or press your hand against a window to feel the cold glass. A ladder rests against the side of a house. In this sense, against means touching or supported by something.

Sometimes against describes resistance or difficulty, like swimming against the current or working against a tight deadline. When something goes against the rules, it breaks them. When the odds are against you, success seems unlikely, but not impossible.

Whether you're arguing against a plan, racing against time, or standing with your back against the door, the word suggests some form of opposition, contact, or resistance.